Data erase method for rewritable phase change type recording medium

ABSTRACT

For an optical recording medium having a phase change type recording layer on its a substrate and having as read only area and a writable area in a recording area, a data recording method is provided which records data in the writable area. This data recording method comprises a transfer step of transferring program data recorded in the read only area in a practical form to an external computer, and an execution step (step A 10 ) of automatically executing the program data in the external computer to record data in the writable area, which can facilitate manufacturing and reduce the possible of destruction or falsification of ROM data.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. application Ser.No. 10/686,760 filed Oct. 15, 2003, now U.S. Pat. No. 7,092,335, whichis a Continuation Application of U.S. application Ser. No. 09/942,277filed Aug. 27, 2001, now U.S. Pat. No. 6,671,249, which is acontinuation of International Application PCT/JP00/09016 filed Dec. 20,2000 and claims priority from Japanese Patent Applications 11-374645filed Dec. 28, 1999 and 2000-67051 filed Mar. 10, 2000, the contents ofwhich are herein incorporated by reference.

TECHNICAL FIELD

The present invention relates to a rewritable phase change type opticaldisc including a ROM area partially, and to a system for performingrewrite in a RAM section without inadvertently overwriting ROM data inthe disc, and more particularly to a ROM/RAM-mixed rewritable compactdisc.

BACKGROUND ART

In the recent years, optical discs have come into widespread use as arecording medium suitable for distribution, duplicate and retention of alarge volume of data. Of these optical discs, a CD-format read only disc(CD-ROM), a recordable disc (CD-R) and a rewritable disc (CD-RW)constitute the most widespread optical disc family. A feature of theCD-ROM, CD-R and CD-RW pertaining to a CD family is an attribution ofdata thereof, with they being used properly on the basis of the dataattributions.

The CD-ROM disc is of a type suitable for use in transferring data ontoa substrate in the form of dented pits for duplicating the data with thesame contents in large numbers. On the other hand, the CD-R or CD-RW isof a type permitting arbitrary additional recording or rewrite of data,and is thus suitable for data retention or the like at private levels.Of these, the CD-RW has been expected as an inexpensive, large-capacitybackup recording medium substituting for floppy discs or MO discs.

A primary difference between a recorded data signal on a CD-RW and adata signal on a conventional CD-ROM (reflectivity of more thanapproximately 60%) is only that the reflectivity is lower byapproximately 15 to 25%, and if the existing drive is designed to handlea low reflectivity, then the compatibility is achievable in a widerange. In fact, many CD-ROM drives have already handled it.

In addition, Japanese Laid-Open (Kokai) No. HEI 11-250522 (whichsometimes will be referred to hereinafter as a “well-known document”)discloses a technique about a hybrid structure including anon-rewritable aluminum reflection area and a rewritable phase changereflection area. According to the technique disclosed in this well-knowndocument, a non-rewritable recording area, which inhibits rewrite anderase through the use of a dedicated format, is provided in a CD-RWmedium while the remaining area is used as a rewritable recording areaso that, for read and write, a dedicated CD-RW drive is employed whichis capable of restricting write/read by the format dedicated to thenon-rewritable recording area.

Still additionally, a large number of drives each capable of recordingon both the CD-R and CD-RW media (also capable of rewriting on theCD-RW) have been designed on the basis of the CD-R drive developed priorto the CD-RW, and put on the market.

Rewritable type discs (Partial ROM, P-ROM) having a read only (ROM) areain a section of its information recording area are preferable because ofenabling both data distribution and user data recording, and the CDfamily is likewise required to realize them.

So far, as a write-once type compact disc (CD-R) or rewritable typecompact disc (CD-RW), there has been proposed a disc (hybrid disc) inwhich, through the use of a multisession format, only a first session isused for ROM data while a second session and sessions subsequent theretoare used as a recordable partial ROM area.

However, for the recording of data in the form of fixed-length packetsthrough the use of a format other than the multisession, there is norule for when specific packets are employed as a ROM area.

Moreover, in the case of the hybrid disc, since the multisession formatprescribed or defined originally for the CD-R is directly used for theCD-RW, considerations are also given to only the recordable functionwith respect to the second session forming a rewritable (RAM) area andsubsequent sessions.

For this reason, there arises a need to realize a ROM/RAM-mixed disc(Partial ROM, P-ROM disc), which has a ROM area comprising a pre-pitsrow and freely rewritable RAM area, by the use of the CD-RW.

With such a ROM/RAM-mixed disc, there is a need to read out data fromthe ROM area and the RAM area without use of separate readout circuits,and there is a need to inhibit substantial distinction from the readoutsystem side.

Meanwhile, in the recording, the writing in the ROM area is impossiblewhile the recorded data in the RAM area is rewritten by overwrite;therefore, there is a need to distinctively deal with both the data inat least a recording system.

As a conventional example, among magneto-optical discs, there exists adisc having a ROM area comprising a pre-pits row partially. The ROM areais coated as a reflective layer with a recording medium identical tothat of the RAM area. However, in the case of the magneto-opticalmedium, the readout of data originally comprising a pre-pits rowinvolves detection of variation in reflectivity strength while thedetection of a magneto-optical signal involving detection of variationin polarization through a complex polarization optical system. That is,since a readout optical system achieves easy distinction, acharacteristic exists that, even if a magneto-optical signal is recordedin a pre-pits row by mistake, this does not affect a signal readoutsystem at all, thus preventing destruction of the ROM data.

In the meantime, also for a phase change medium, in view ofmanufacturing, it is also preferable that the ROM/RAM areas have thesame multilayer structure. However, since the readout signal from theROM area comprising a pre-pits row and the readout signal from the RAMarea are obtainable through the use of the same optical system, a phasechange recorded signal (physically rewritable signal obtainable by amark row formed on the basis of the difference in property from aperipheral area in a phase change recording layer), by contrast, isoverwritten on the pre-pits row to superimpose a RAM recording signal onthe pre-pits data, which can destroy the ROM data.

Currently, although there is an example in which write inhibit is madein units of files on an operating system and the definition of a readonly file takes place, the reliability is low because of easyalteration/falsification. No prescription about write inhibit or ROMdata attribution exists, as it is, at the logical format level in unitsof bits or blocks of digital data in lower-order than file attribution.

In the case of a P-ROM disc using a phase change medium, a recordingsystem is required to recognize a ROM area without depending upon anoperating system, or to inhibit rewriting in a recorded area andrecognize it as a ROM area thereafter. In particular, a phase changetype CD-RW disc, prescribed such that an intended read only compact discand data format/readout signal are the same in physical characteristics,is required to seize a ROM area and a RAM area in a recording system.

Among concrete applications for a P-ROM utilizing a phase change medium,there are textbooks for use in repeated practice of languages or musicpresented in the form of CDs. In such applications, a sentence of aforeign language or a measure of a music, serving as a model(demonstration), is read out as application data to call upon a user torepeat it, and the user immediately records the repeated contents to putthem as new input information in a user data area.

Heretofore, although such an application has been done with a cassettetape, after the demonstration, i.e., readout, a need for complex worksexists, such as head search of a tape and switching to readout/recordingmodes for recording the “repetition”. Although there are some casesusing a solid-state memory device instead, since limitation is imposedon the recording capacity, difficulty is experienced in dealing with alarge volume of demonstration data for a long period of time. Inaddition, because of the employment of a high-class compressiontechnique to reduce data volume, a delicate nuance, which is said to benecessary for the practice of languages or music, can drop out from thedata. With a capacity of 650 to 700 MB like CD-RW, it is possible toaccumulate voice data equivalent in quality to that of CD even withalmost no compression, or to further increase the voice data volumethrough the use of a voice compression technique such as MP3.

The employment of an image compression technique such as JPEG or MPEG1enables still picture and moving picture demonstrations and recording.

Meanwhile, in general, the demonstration is divided in units of severalseconds to several tens seconds in order to facilitate the repetition,and the recording of the demonstration and user data are required to bemade repeatedly within a given time length, so there is a need toshorten the time needed for the switching in recording between thedemonstration and the user data to the utmost.

Accordingly, if an application program is stored on one CD-RW disc andthe program and demonstration data are read out therefrom to conduct thedemonstrations and user data involving repeated data is then recorded onthe same CD-RW disc, this is extremely convenient, for that recordingand readout become feasible with the same recording/readout apparatus.

Moreover, commonly, for such an application, two kinds of data: a mainroutine comprising an executive program and a demonstration datacollection comprising a plurality of contents, are collected as ROMdata. For example, here the main routine is such a program as a menuscreen appears as an user interface to execute various types ofprocessing according to selection by the user. When the user selects theexecution of a specified demonstration in the menu screen, selected datais acquired from the demonstration data collection so that thedemonstration is implemented by means of a program of the main routine.

In this case, if the user updates only the demonstration data collectionwithout changing the main routine, discs for the purpose of small-volumemany-kind application distribution are producible with high efficiency.In view of the actual circumstance of computer-aided publishing, anextremely urgent and important requirement is that, instead of a simpleCD-ROM, small-volume many-kind application discs are produced as ROMdata capable of updating partially.

It is an object of the present invention to provide a P-ROM, datarecording method, data readout method and data erase method easy toproduce and providing less possibility of destruction or falsificationof ROM data, and more particularly to provide an optical recordingmedium, data recording method for rewritable phase change type opticaldisc, data erase method for rewritable compact disc, data erase methodfor rewritable phase change type recording medium, read only data erasemethod, and recording/readout apparatus.

More concretely, the present invention relates to a rewritable compactdisc having both a read only area and rewritable area.

DISCLOSURE OF INVENTION

For the foregoing purpose, in accordance with a first point of thepresent invention, there is provided an optical recording mediumcomprising a substrate having a phase change type recording layer, andhaving a read only area and a rewritable area in its informationrecording area, wherein the read only area and the rewritable area havethe same multilayer structure, and data and address information in theread only area and the rewritable area comprise basic data units havingthe same logical structure, and auxiliary data capable of distinguishingbetween read only data and rewritable data is provided in the unit or ina data unit including a plurality of data units each corresponding tothe unit.

Accordingly, this enables handling intended rewriting data as logicalROM data. Moreover, for example, a CD-RW is apparently used as awrite-once type medium.

In addition, in accordance with a second point of the present invention,in the arrangement of the optical recording medium according to theabove-mentioned first point, an address to be added to the basic dataunit and the auxiliary data are written previously on the substrate inthe rewritable area and the read only area.

Still additionally, in accordance with a third point of the presentinvention, in the arrangement of the optical recording medium accordingto the above-mentioned first or second point, information in the readonly area is obtained by a plurality of pre-pits rows made on thesubstrate.

Moreover, in accordance with a fourth point of the present invention, inthe arrangement of the optical recording medium according to theaforesaid second point or third point, a groove is formed in therewritable area to have a wobble made so that a center line thereofshows a predetermined amplitude with respect to a recording/readoutoptical beam scanning direction, while a center line of a pre-pits rowin the read only area wobbles to show an amplitude substantially equalto the amplitude of the groove with respect to the optical beam scanningdirection, and consecutive address information is given by the wobble ofthe groove and the wobble of the center line of the pre-pits row.

Still moreover, in accordance with a fifth point of the presentinvention, in the arrangement of the optical recording medium accordingto the aforesaid fourth point, a carrier frequency due to the wobble ofthe groove and the wobble of the center line of the pre-pits row isfrequency-modulated or phase-modulated with digital information toprovide auxiliary data.

Accordingly, with this arrangement, in a P-ROM disc in which a physicalROM area comprising pre-pits or the aforesaid logical ROM area and a RAMarea are formed in a mixed state and they are covered with a phasechange medium, it is possible to overwrite the ROM data, thus preventingthe destruction and falsification of the ROM data.

In addition, in accordance with a sixth point of the present invention,in the optical recording medium according to the aforesaid first point,information in the read only area is acquired by a mark row formed onthe basis of a difference in optical characteristics from a peripheralarea in a phase change recording layer, and write inhibiting processingis conducted with respect to the mark row.

Thus, a rewritable area with a write-once (first-time writable)attribution is distributed to a user in a non-recorded state so that theuser receives it as a pseudo write-once medium which permits write-once(first-time writable).

Still additionally, in accordance with a seventh point of the presentinvention, in the arrangements of the optical recording media accordingto the aforesaid first to sixth points, fixed-length data is used as thebasic data unit containing the auxiliary data.

Thus, it is possible to surely provide a data attribution representativeof whether it is “rewritable” or “read only”, at a lower level in arecording/readout drive unit.

Moreover, in accordance with an eighth point of the present invention,in the arrangements of the optical recording media according to theaforesaid first to seventh points, data in an information recording areais an eight to fourteen modulation signal (EFM signal) compatible with acompact disc.

Still moreover, in accordance with a ninth point of the presentinvention, in the arrangement of the optical recording medium, aprescription on the rewritable attribution or the read only attributionis placed in an absolute time in pre-groove (ATIP) frame.

Furthermore, in accordance with a tenth point of the present invention,in the arrangement of the optical recording medium according to theaforesaid ninth point, ATIP information is stated in terms of anabsolute time of a two-digits BCD code in units of minutes, seconds orframes, and when the most significant bits in eight bits for expressionof the minute, second and frame are respectively taken as M1, S1 and F1,the attribution is prescribed in a state associated with any one of (0,0, 0), (0, 0, 1), (0, 1, 0) and (0, 1, 1) of (M1, S1, F1) in a programarea.

Still furthermore, in accordance with an eleventh point of the presentinvention, in the arrangement of the optical recording medium accordingto the aforesaid eighth point, a prescription on the rewritableattribution or the read only attribution is placed in an EFM frame.

Yet furthermore, in accordance with a twelfth point of the presentinvention, in the arrangement of the optical recording medium accordingto the eleventh point, the attribution of a frame specified by thesubcode is prescribed in a state associated with specific two bits in aQ-channel of the subcode.

In addition, in accordance with a thirteenth point of the presentinvention, in the arrangement of the optical recording medium accordingto the eighth point, a prescription on the rewritable attribution or theread only attribution is placed in a block.

Still additionally, in accordance with a fourteenth point of the presentinvention, in the arrangement of the optical recording medium accordingto the thirteenth point, the attribution of the block is prescribed in astate associated with specific two bits in a plurality of bitsdescribing mode information included in a header of the block.

Moreover, in accordance with a fifteenth point of the present invention,in the arrangements of the optical recording media according to thefirst to fourteenth points, the attribution on whether or not to berewritable includes an attribution on whether or not to be rewritableonly one time and an attribution on whether or not to be writablerepeatedly.

Still moreover, in accordance with a sixteenth point of the presentinvention, in the arrangements of the optical recording media accordingto the eighth to fifteenth points, a program area is divided into aplurality of sessions according to a prescription of a multisessionformat so that some of divided sessions are used for read only while theother sessions are made rewritable.

Yet moreover, in accordance with a seventeenth point of the presentinvention, in the arrangement of the optical recording medium accordingto the sixteenth point, the program area is divided into a first sessioncomprising read only data having an ISO9660 file structure and a secondsession comprising a rewritable type area so that user data and lead-outin the first session are handled as read only data while a lead-in area,a program memory area (PMA) and a power calibration area (PCA) are maderewritable.

Furthermore, in accordance with an eighteenth point of the presentinvention, in the arrangement of the optical recording medium accordingto the sixteenth point or seventeenth point, information representativeof whether the session pertains to the rewritable attribution or theread only attribution is included in a lead-in area of each session ofthe multisession format.

Still furthermore, in accordance with a nineteenth point of the presentinvention, in the arrangement of the optical recording medium accordingto the eighteenth point, information representative of an opticalrecording medium having a read only area and a rewritable area isincluded in special information of the lead-in area or the lead-in areaof the first session of the multisession format stated with ATIP.

Yet furthermore, in accordance with a twentieth point of the presentinvention, in the arrangement of the optical recording medium accordingto the eighth to eighteenth points, information representative of anoptical recording medium having a read only area and a rewritable areais included in EFM data of the lead-in area or the lead-in area of thefirst session of the multisession format.

Accordingly, with this arrangement, three types of data areas of amaster ROM, a post ROM and a RAM can be formed in a state mixed on thesame disc. In addition, owing to the ATIP, a rewritable area having awrite-once attribution is usable as a pseudo write-once medium on theuser side, and the master ROM area is producible on the user side.

In addition, in accordance with a twenty-first point of the presentinvention, there is provided a data recording method for use in arewritable phase change type optical disc which has a phase change typerecording layer on its substrate and which has a read only area and arewritable area in its information recording area, comprising of atransfer step of transferring program data recorded in the read onlyarea in a practicable form to an external computer and an execution stepof automatically executing the program data in the external computer torecord data in the rewritable area.

Thus, this enables conducting doubled write inhibiting processing on thesystem, thus enhancing the reliability about the ROM data destructionprevention, besides the complete compatibility with the existing formatsis achievable.

Still additionally, in accordance with a twenty-second point of thepresent invention, in the arrangement of the optical recording mediumaccording to the foregoing first point, identification informationrepresentative of a rewritable type including a partial read only areais written previously on the substrate in the form of pre-pits or awobble.

Moreover, in accordance with a twenty-third point of the presentinvention, in the arrangement of the optical recording medium accordingto the foregoing twenty-second point, data in the read only areacomprises a pre-pits row, and address information in the read only area,together with the identification information, is written previously onthe substrate in the form of pre-pits or a wobble, and further filemanagement information on a file included in the read only area and therewritable area is written in the rewritable area.

Thus, this enables recognizing that, when a disc is inserted into arecording drive, it is a P-ROM disc, and acquiring file managementinformation about the ROM area to save it in a memory on the system. Inaddition, it is possible to prevent only the file management informationfrom being erased or the disc from being initialized due to overwrite inerror to make the access to the ROM area difficult, or to prevent theROM data from being destroyed by the overwrite without recognizing thepresence of the ROM area. Still additionally, the ROM data comprising apre-pits row is erasable by overwriting different data from the ROM datain the phase change type recording layer in the read only area havingthe ROM data, so the factory or software manufacturer side, for example,can certainly keep data, undesirable to show to the user side, insecret.

Still moreover, in accordance with a twenty-fourth point of the presentinvention, there is provided a data erase method for use in a rewritablephase change type recording comprising a substrate medium having a phasechange type recording layer, and having a read only area and arewritable area in its information recording area, comprising arecognition step of recognizing identification information previouslywritten in the form of pre-pits or a wobble on the substrate andrepresentative of that the recording medium is of a rewritable typeincluding a read only area comprising partially a pre-pits row orwobble, a memory transfer step of acquiring address information from theread only area for transferring the address information to a storageunit, an erase step of erasing file management information written in afile management area of the recording medium, and a re-recording step ofrecording, the address information of the read only area, transferred tothe storage unit, into the file management area.

Yet moreover, a twenty-fifth point of the present invention has anarrangement comprising an identification step of identifying, on thebasis of information recorded in a lead-in area of the first sessionarea in a compact disc with a multisession format having a plurality ofsession areas each including a lead-in area, that the compact disc is ofa rewritable type having a read only area, an extraction step ofextracting an attribution about rewrite, write-once (first-timewritable) or write inhibit (read only) from each of the lead-in areas ofthe plurality of session areas, a memory transfer step of, when theattribution extracted in the extraction step is about the write inhibit(read only), transferring a file structure of the write inhibit (readonly) session area to a storage unit, an erase step of erasinginformation recorded in the lead-in area of the first session area, anda re-recording step of recording the disc identification information,the file structure of the write inhibit session area transferred to thestorage unit and a leading address of a rewritable area.

Thus, this enables avoiding the erase of ROM data due to directoverwrite, and further preventing the erase of the ROM data stemmingfrom the failure of a simple erase operation.

Furthermore, in accordance with a twenty-sixth point of the presentinvention, in the arrangements of the optical recording media having apartial read only area, according to the foregoing first to twentieth,twenty-second and twenty-third points, has the read only area includinga first read only area in which data is recorded in the form of apre-pits row and a second read only area formed by inhibiting re-writeafter recording of data and has the rewritable area.

Still furthermore, in accordance with a twenty-seventh point of thepresent invention, in the arrangement of the optical recording mediumaccording to the foregoing twenty-second point, a predeterminedupdating-unnecessary application program is stored in the first readonly area, and an updating-possible or customized application program isstored in the second read only area, and further a user data recordingarea capable of recording user data related to at least the applicationprogram is provided in the rewritable area.

Thus, this enables ROM data to be impossible to be falsified, erased anddestroied, and making at least a recording drive seize a ROM area.

Yet furthermore, in accordance with a twenty-eighth point of the presentinvention, there is provided a recording/readout apparatus in which anapplication program area containing data of a predetermined applicationprogram is formed as a read only area with a read only attribution inspecified consecutive areas existing in a program area and a user datarecording area capable of recording user data related to at least theapplication program is set as a rewritable area with a rewritableattribution in the remaining program area of the specified consecutiveareas and which is made to read out the application program andrecord/read out the user data related to the application program, theapparatus comprising recognition means for, when a medium is mounted,recognizing that it is a rewritable phase change type optical dischaving a partial read only area partially, program execution meanscapable of gaining access to the read only area recognized by therecognition means to acquire the application program data for executingthe contents of the program, information input means capable ofinputting required information in accordance with the applicationprogram executed by the program execution means, and recording meanscapable of gaining access to the user data recording area to record, asuser data, the information inputted by the information input means.

With this arrangement, in addition to, for example, language practice,it is possible to store a first-version application program in a masterROM area and store only a portion, needed for correction of the program,in a post ROM area when a need for a partial version-up of the programexists.

Moreover, in accordance with a twenty-ninth point of the presentinvention, there is provided a read only data erase method for use in anoptical recording medium in which a phase change type recording layer isformed on a substrate and read only data is made by a plurality ofpre-pits rows formed on the substrate, wherein data different from theread only data is overwritten in the phase change type recording layerfor making impossible the readout of the read only data.

Thus, this enables the factory or software manufacturer side, forexample, to erase a portion of data to be updated in a master ROM area.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1( a) is an illustrative view showing a guide groove in a datanon-recorded rewritable area.

FIG. 1( b) is an illustrative view showing a guide groove in a read onlyarea comprising a pre-pits row.

FIG. 2 is an illustration of waveforms of an analog signal of an EFMsignal.

FIG. 3( a) is an illustrative view showing a multilayer structure of aCD-RW disc to which the present invention is applied.

FIG. 3( b) is an illustrative view showing a dent section of a CD-RWdisc.

FIG. 4( a) is an illustration for explaining an area of a CD-RW disc towhich the present invention has application.

FIG. 4( b) is a perspective view showing a CD-RW disc to which thepresent invention is applied.

FIG. 5 is an illustration of a data structure in ATIP.

FIG. 6 is a flow chart showing file write utilizing ATIP.

FIG. 7 is an illustration of a block in which 98 frames are arranged.

FIG. 8 is an illustration of a Q-channel data structure.

FIG. 9 is a flow chart showing file write utilizing an EFM signal.

FIG. 10 is an illustration of a packet structure in the case offixed-length packet recording.

FIG. 11 is a flow chart showing file write utilizing a blockattribution.

FIGS. 12( a) to (d) are illustrations of an area configurationcorresponding to a P-ROM format.

FIG. 13 is an explanatory illustration of an example of an areaconfiguration of a CD having a multisession format partitioned intothree sessions.

FIG. 14 is a flow chart showing an attribution decision according tosession in the case of multisession.

FIG. 15 is a flow chart showing one example of a simple erase method fora P-ROM.

FIG. 16 is a flow chart showing one example of an automatic executiveoperation for ROM data.

FIG. 17 is an illustration of one example of a P-ROM data arrangement.

FIG. 18 is a flow chart for explaining a P-ROM recording/readout method.

FIG. 19 is an illustration of a configuration of a recording/readoutsystem according to an embodiment of the present invention.

FIGS. 20( a), (b) are partial enlarged views, from above, illustrativelyshowing a P-ROM on which auxiliary data is written between grooves or inflat portions between pre-pits rows.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described hereinbelow withreference the drawings.

A recording medium according to the present invention is such that aphase change type rewritable recording layer is formed on a substrate.There has hitherto been an example in which a read only information onlya recording/readout system can gain access to is written other than auser data writable recording area, whereas in the present invention aread only area is essentially provided in a user data recordablerecording area.

A recording area (program area) of a medium according to the presentinvention includes both a read only area and rewritable area, while amedium with the same layer configuration is used irrespective of adifference in attribution therebetween. In general, such a medium iscomposed of a phase change type recording layer, a protective layerformed to cover at least one side of the phase change type recordinglayer, a reflective layer placed on the opposite side to arecording/readout light incidence side of the recording layer, and otherlayers. Commonly, these layers are all formed by a sputter technique.Regardless of deposit methods, if a recording area is made to have thesame multilayer structure and is formed by the same manner, then thissimplifies a manufacturing process and is desirable from the viewpointfrom a decrease in manufacturing cost. Accordingly, even a ROM area isphysically coated with a rewritable phase change type recording layer.

In the present invention, a classification into two types takes placeaccording to ways of giving read only information in a ROM area. One isthat a surface of a substrate is deformed, that is, user data is writtenthrough the use of a pre-pits row based on irregularities or a wobbleand is overcoated with the aforesaid phase change type recording layer.The other is that, after data is recorded (first-time recorded) in theform of a phase change in a partial area, a recording system conductsprocessing to inhibit re-write in this area (write inhibitingprocessing). In the present invention, the read only (ROM) data recordedin the form of a pre-pits row(s) will be refereed to hereinafter as“master ROM data”, while data made non-rewritable through the writeinhibiting process after recorded and handled as read only will bereferred to hereinafter as “post ROM data”. In the present invention,commonly, the post ROM data is given as a phase change recording signal,that is, a physically rewritable signal obtained by a mark row formed onthe basis of a difference in optical property from a peripheral area inthe phase change type recording layer. In this connection, in theinvention, when a specified area (formed with substantially consecutiverecording tracks and addresses) of a program area is filled with ROMdata, this area will be called a ROM area.

In the present invention, for production of a host ROM, a writeinhibiting attribution (read only) is added previously to a non-recordedrewritable area, but in some cases, a factory or software manufacturerside uses a special recording drive to make a user side confirm theaforesaid read only area as a read only area after distributed.

In addition, there is a possibility that a factory or softwaremanufacturer side rewrites data once or several times for editingpurposes or gives new write inhibiting attribution (read onlyattribution) to edited data after the completion of editing, beforedistributing to users.

On the other hand, it is also possible that a rewritable area equippedwith a write-once (first-time writable) attribution is distributed to auser in a non-recorded state and is given as a pseudo write-once mediumbeing of a type recordable once (first time). In this case, afterone-time recording (first-time recording) on the user side, rewritebecomes impossible. That is, even if the rewritable area is of aphysically rewritable type, on the user side, it functions as anon-recorded write-once medium. In addition, if the factory or softwaremanufacturer side makes recording in the write-once area and distributesit to the user, likewise the user side can use it as a read only areabecause of being non-rewritable on the user side.

Meanwhile, rewritable data will be referred to as “RAM data”, while aportion of a recording area filled with the RAM data will be referred toas “RAM area”. The RAM data is not always recorded in the RAM area fromthe beginning, and the RAM area is an area in which data is rewritableand which is not subjected to the write inhibiting processing.

The present invention proposes a method in which attributionscorresponding to “read only” and “rewritable” are added to data and areidentifiable in at least a recording system, and further a medium whichincludes both data areas prescribed as a ROM and RAM in terms of theattribution. In the invention, the data attribution is set for eachbasic unit of data. Here, the data basic unit is a unit to be processedcollectively in data processing of a recording/readout drive unit, forexample, in the case of a CD format, an ATIP frame in unit of 1/75seconds in the ATIP and a 98 EFM frame of EFM data equipped with asubcode, while in the case of a CD-ROM format, a block comprising dataof 2352 bytes. A packet comprising a plurality of blocks (usually, 16 or32 blocks) is also considered as a basic unit. These are examples inwhich each data unit capacity is a constant fixed-length data unit. Inaddition, it is also possible that a ROM or RAM area per se iscollectively considered as a track in a CD format, or that, in a case inwhich a session is established according to a prescription of a CDmultisession format, the session is considered as one unit. Stilladditionally, a packet forming a group of fixed-length blocks which isnot necessarily constant in number can also be considered as one dataunit. This is an example of a variable-length data unit which is notfixed in data unit capacity.

More generally, user data is partitioned in units of 2^(n) bytes (512,1024, 2 k, 4 k, 16 k, 64 k, . . . , and other bytes), and redundancedata such as parity bits for error is added thereto to produce a logicalminimum basic data unit. Additionally, when a plurality of data units(not limited to fixed length), each corresponding to this basic dataunit, are grouped, the grouped data unit is also treated as one kind ofbasic data unit. Moreover, an address or auxiliary data on dataattribution is added according to basic data unit.

In the present invention, preferably, fixed-length data, particularly,an address added minimum unit, is employed as the basic data unit. As aresult, it is possible to certainly add a data attribution indicative of“rewritable” or “read only” at lower levels (close to hardware and hardto cover by an operation by a user) of a recording/readout drive unit. Adata attribution can also be added to a variable-length data unit formedby grouping a plurality of fixed-length data units; also in this case,it is preferable that the same data attribution is added in units oflow-level fixed-length data units.

It is also appropriate that the address included auxiliary data is addedto construct a series of bit strings as bit information like the basicunit of the user data, or that the address included auxiliary data isadded in a state adjacent to the basic unit of the user data andseparated spatially by a different type of signal.

An example of the former is an additional bit string called a subcode inan EFM signal in a CD format which will be mentioned later, while anexample of the latter is auxiliary data (ATIP information) depending ona wobble used in CD-R or CD-RW. Alternatively, the auxiliary data to beadded can also be a pit row placed between grooves or between pre-pitsrows, or a pit row situated before and after a user data string of abasic data unit.

In any case, it is preferable that attribution information of a basicdata unit indicative of “read only”, “write-once (first-time writable)”or “(repetitive) rewritable”, together with address information, ispreviously written as “non-rewritable” information on a substrate. Thatis, an address allocated to each basic data unit is previously writtenon the substrate and the data attribution to be recorded at that addressis written in advance at every address, and in this case, it ispreferable that the writing manner is stated with a non-rewritablesignal. If a design is made such that the recording drive side recordsdata with a predetermined attribution at a predetermined address inaccordance with that data attribution information, then this makes itdifficult to readily alter the data attribution on the user side, whichreduces a possibility of destroying data in a read only area due tooverwrite by phase change recording.

Although the non-rewritable signal, mentioned here, is achievable byforming a physical deformation such as a wobble on a substrate byinjection molding, if “non-rewritable on the user side”, it is alsoacceptable to use a recording signal depending on the phase changerecording. The recording signal of “non-rewritable on the user side” isa signal which is inhibited to rewrite in the user side by means of aspecial processing such as cipher.

Accordingly, an address and auxiliary data to be added to a basic dataunit are previously written in a rewritable area and a read only area ona substrate.

In this case, each of the data, data attribution and address informationin a ROM area has the same logical structure as that in a RAM area. Thatis, they have the same basic data unit, and are made such that the userdata is partitioned according to the aforesaid basic unit and the dataattribution and address information are added thereto. In consequence,the readout (decode) becomes feasible with the same readout (logical)circuit.

In the RAM area, usually, a concentric or spiral guide grooves are madeto allow the guide of an optical beam even in a non-recorded condition.In addition, at this time, it is preferable that a predeterminedamplitude is made with respect to a scanning direction of the opticalbeam. By giving information through the wobble, it is possible todistinguish between a non-rewritable area and a rewritable area. In thecase of a disc-like medium, since a guide groove is usually formed intoa concentric or spiral configuration, an optical beam takes a scanningaction along an almost circumferential direction to follow the guidegroove, and the wobble is made to establish an amplitude in radialdirections.

Also in a post ROM area, because the recording is made initially, it ispreferable to form a guide groove similar to the above-mentioned guidegroove.

Furthermore, although a pre-pits row is made in a master ROM area, inthis case, it is preferable that pre-pits are made so that the centerline of the pre-pits row has a wobble with the almost same signalamplitude as that of the aforesaid guide groove with respect to ascanning direction of a recording/readout optical beam. As a result, itis possible to provide continuous address information in the master ROMarea and the rewritable area. In the present invention, including thecenter line of a pre-pits row, a guide groove is used in a wide sense.

In the present invention, it is particularly preferable that an addressis given previously on a substrate through the change of a wobble.Particularly, in a non-recorded RAM area, for access to a predeterminedposition, referring to an address depending on a wobble shown in FIG. 1(a) has come into widespread use. In FIG. 1( a), in a rewritable area 51,a guide groove 50 is a dented portion defined by being surrounded bygroove wall surfaces 50 a and 50 c, and usually is formed bytransferring a projecting configuration of a stamper onto a substrate.In addition, address information is given by a wobble of the guidegroove 50, and it is acquired in a manner that laser light reads thisgroove configuration.

The address depending on the wobble can be given in a manner that a wave(carrier wave) with a constant frequency is frequency-modulated(FM-modulated) or phase-modulated with digital data of “0” and “1”.

In the wobble equipped with address information, particularly, theaddress allocated along the guide groove by the wobble is alsoapplicable to the concept of the guide groove in the wide sense, andwhen, as shown in FIG. 1( b), the actual center line 50 b of a pitsequence (pre-pits row) 52 is wobbled at a frequency equal to that ofthe groove 50 of the RAM section, whichever of the master ROM, the postROM and the RAM area, the addition of address becomes feasible with awobble depending on a continuous carrier wave. Moreover, in addition tothe address, another additional information can also be added.

Since it is desirable that the readout system can gain access andaccomplish the readout without distinguishing between the ROM area andthe RAM area, it is preferable that the ROM area and the RAM area haveaddress information with consecutive serial numbers. This addressinformation is given in the form of the above-mentioned wobble and alsois included as a part of the recording data. In the case of beingincluded as a part of the recording data, the address information havingthe same logical structure can be given as the data in the RAM area andthe ROM area are made with the same format. In addition, in the case ofutilizing the wobble in the wide sense as shown in FIG. 1( b), if theamplitude of the wobble 50 in the RAM area is almost equal to theamplitude of the wobble of the actual center line of a pre-pits row 52in the master ROM area, the address information can continuously be readout over the entire area by means of one wobble readout circuit. In thiscase, the almost equality signifies the degree that the signalamplitudes almost equal to each other are obtainable in a wobble signalreadout circuit, and usually, the magnitude of one amplitude is set tobe less than twice the magnitude of the other amplitude.

In general, a push-pull signal readout circuit is used for the readoutof the wobble, in both the cases shown in FIGS. 1( a) and (b), thereadout circuit is applicable. Incidentally, the push-pull signalcircuit is for detecting diffracted light reflected from a groove ordent-like pit through the use of a two-piece detector formed in a statedivided into right and left sides with respect to the groove tocalculate a difference therebetween, and is a technique well known bythose skilled in the art.

As a matter of course, it is preferable that a ROM signal comprising apre-pits row and a recorded signal in the RAM area on the phase changerecording are decoded with the same logic circuit according to the samemodulation mode. In addition, for the readout by the same readout unit,the recording signals in both the areas are required to have thesubstantially same reflectivity and modulation amplitude. For example,usually, in the case of a signal involving a dent-like pre-pit in aCD-ROM, because the reflectivity lowers at a pit position due to a phasedifference of the reflected light, it is preferable that, even in theRAM area, the reflectivity is high in a non-recorded state while thereflectivity is low in a recorded state. In the phase change typerecording layer, usually, a non-recorded state corresponds to acrystalline while a recorded state corresponds to an amorphous state.However, the reversal thereof is also acceptable, and it is alsopossible to associate different crystallines with each other.

In the present invention, likewise, the master ROM area has the samemultilayer structure as that of the RAM area, and it is difficult thatthe readout system distinguishes between the ROM area and the RAM area.In addition, in not only the post ROM area but also the master ROM area,it is physically possible to overwrite data in the phase change typerecording layer itself; therefore, for falsification prevention, eraseand destruction prevention of ROM data, there is a need for at least therecording drive to recognize that it is the ROM area.

For this reason, it is preferable that identification informationindicative of that it is a P-ROM is written in a specified area of therecording medium in order to make the recording system recognize arewritable type medium (P-ROM) in which the phase change type recordingmedium partially has a read only area, and it is more preferable thatthe identification information is previously written on the substrate asthe master ROM data such as pre-pits or wobbles.

Accordingly, the identification information representative of therewritable type including a partial read only area is previously writtenon the substrate in the form of pre-pits or wobbles.

Furthermore, in the present invention, it is preferable that, regardlessof whether in the ROM area or in the RAM area, file managementinformation of the user data recorded in each area is written in the RAMarea together. In this case, there is a need to prevent the filemanagement information in the ROM area from being further lost in errordue to the erasure or the overwriting of the file management informationof the RAM data. For this reason, it is preferable that the addressinformation for the access to the ROM area is also written (registered)previously as the master ROM area in the above-mentioned specified area.

Still furthermore, in the present invention, it is possible that agrouped ROM area or RAM area comprising consecutive addresses isconsidered as a variable-length data unit and a data attributionindicative of ROM or RAM is given at every variable-length data unit. Inaddition, for at least the ROM area, it is desirable that ROM areaaddress information each composed of a variable-length data unitcomprising the consecutive addresses, preferably together with the dataattribution, are registered collectively in a specified area of thedisc. As the address information to be registered, it is preferable toregister not only a start address of each area but also a length (size)thereof or an end address together.

More preferably, disc identification information capable of identifyingwhether the disc is of a read only type having only a read only area, arewritable type (P-ROM) having a partial read only area or a rewritabletype having only a rewritable area is written in a specified area on thedisc.

Thus, the data in the aforesaid read only area comprises a pre-pits row,and the address information in the read only area, together with theidentification information, is previously written on the substrate inthe form of pre-pits or wobbles, while the file management informationon files included in the read only area and the rewritable area iswritten in the rewritable area.

With this arrangement, when a disc is inserted into the recording drive,it is possible to recognize that it is a P-ROM disc, and to acquire thefile management information on the ROM area for saving it in a memory onthe system. Such a means is effective in erasing only the filemanagement information, and in preventing the disc from beinginitialized by overwriting in error to make difficult the access to theROM area or the ROM data from being destroyed by the overwriting withoutrecognizing the presence of the ROM area.

In this connection, if, in the read only area, particularly, in themaster ROM area, its file management information such as a startaddress, size, end address or the like is written as master ROM datasuch as a pre-pit or wobble also in the file management area, it ispossible to reduce a possibility of erasing in error by the aforesaidinitialization. Not only in a case in which the file management area isplaced into a non-recorded state but also when overwriting is madetherein, the master ROM data can again be read out by returning to thenon-recorded state.

On the other hand, it is also possible to erase the ROM data byoverwriting data different from the ROM data in the phase change typerecording layer of the read only area having the ROM data comprising apre-pits row. In this case, for example, here a factory or softwaremanufacturer side can certainly keep data, undesirable to show to theuser side, in secret.

That is, with respect to a medium having both the master ROM area and apost ROM area, in a using method (which will be described later) ofupdating a part of application software data included in the master ROMarea to re-record it in the post ROM area, for example, the factory orsoftware manufacturer side can erase a part of data to be updated in themaster ROM area(s) through the use of the above-mentioned erase method.

Thus, an erase method for read only data according to the presentinvention is an erase method of erasing read only data in an opticalrecording medium in which a phase change type recording layer is formedon a substrate and read only data is formed in the form of a pluralityof pre-pits rows made in the substrate, wherein data different from theread only data is overwritten in the phase change type recording layerto make difficult the readout of the read only data.

In the present invention, in particular, it is preferable thatpredetermined data attribution is included in auxiliary data to be addedto a basic data unit forming an address added minimum unit.

In one useful mode of an optical recording medium according to thepresent invention, data in a recording area is an EFM signal compatiblewith compact discs. Accordingly, although details of the presentinvention will be described hereinbelow using a format and terminologyof CD and CD-RW, if the effect is the same, the invention is not limitedto the CD format per se.

Incidentally, the general information about the CD format which will bedescribed hereinbelow is disclosed in “CD Family”, written by HeitaroNakajima, Takao Ibashi and Hiroshi Ogawa, Ohmsha, “Compact Disc Book”,written by Heitaro Nakajima and Hiroshi Ogawa, Ohmsha, “CD-R/RW OfficialGuide Book”, written by Orange Forum, EXCEED PRESS CO., JapaneseLaid-open (Kokai) No. HEI 11-250522, and other documents.

(A) Description of Embodiment of the Invention

As the logical data structure for CD, there are two types: a logicalformat prescribed by the rule of the Red Book and mainly suitable formusic data and a format prescribed by the Yellow Book and suitable fordata recording in general-purpose block unit forming the InternationalStandard ISO9660. A principal description will be given hereinbelow of aformat, called mode 1, of data recording CD-ROM formats. The differencein mode involves a structure of user data, a difference of contents oferror correction information to be added to the user data, or the like,which does not affect the essence of the present invention.

On the other hand, the CD-RW is prescribed in the Orange Book Part 3.The logical data structure recorded is basically according to theCD-ROM, and the readout is feasible through the use of a readout circuitfor the CD-ROM. An EFM random signal recorded has readout signalwaveforms shown in FIG. 2, and if it satisfies the requirements that theconversion of I_(top) into a reflectivity shows 15% to 25%, the ratioI₁₁/I_(top) of an amplitude I₁₁ of 11T mark and I_(top) is 0.55 to 0.7,and the jitter of mark length and space length of each mark of 3T to 11Tis below 35 nsec at a CD linear velocity of (1.2 to 1.4 m/s), it can beread out as a CD compatible signal with a drive for a rewritable typecompact disc.

FIG. 3( a) is an illustrative view showing a multilayer structure of aCD-RW disc 10 to which the prevent invention has application. The layerstructure of the CD-RW disc shown in FIG. 3( a) is a multilayerstructure, and is made up of a substrate (polycarbonate substrate) 110 fin which a guide groove and/or dents 49 forming pre-pits can be made inits surface, protective layers 110 e and 110 c for controllingabsorption of laser light in a phase change type recording layer(recording layer) 110 d and for adjusting the reflectivity by themultiple interference effective and further for controlling heatradiation from the recording layer to prevent heat deformation of therecording layer or the substrate, the recording layer 110 d of a phasechange type medium made to cover the substrate 110 f and to permit theformation of an amorphous mark capable of generating a readout signalsubstantially corresponding to the dents 49 configuration made in thesubstrate 110 f, and a reflective film 110 b comprising a reflectingmember placed on the opposite side to the recording/readout lightincidence side of the recording layer in order to reflect laser lightand to promote the radiation from the recording layer. In thisconnection, a protective coat 110 a is for protecting a surface of anoptical disc from being damaged. It is also appropriate that, instead ofcovering it along the surface configuration of the dent 49 as shown inFIG. 3( b) which will be described later, the protective coat 110 a isformed to cover the surface in such a manner as to fill in the dent 49.

A focused laser beam for recording/readout arrives at the recordinglayer 110 d after passing through the substrate 110 f. In this case, theCD-RW recording/readout is conducted with an optical system having awavelength of approximately 780 nm and a focusing lens numeric apertureNA of approximately 0.5.

FIG. 3( b) is an illustrative view showing a dent 49 of the CD-RW disc10. In FIG. 3( b), the dent 49 is made to regenerate the configurationof the substrate layer 110 f. In addition, in most cases, every layer isdeposited by a sputter technique. Still additionally, irrespective ofdeposit methods, the same multilayer is taken for the recording area,which simplifies the manufacturing process and reduces the manufacturingcost.

FIG. 4( a) is an illustration for explaining an area of a CD-RW disc towhich the present invention has application, and FIG. 4( b) is aperspective view showing a CD-RW disc to which the invention hasapplication.

The CD-RW disc 10 shown in FIGS. 4( a) and 4(b) has a data structurecomprising a PCA (Power Calibration Area), a PMA (Program Memory Area),a lead-in area, a program area and a lead-out area in the order from theinnermost circumference. Of these, the PCA serves as a trial write areafor determination of the optimum recording power, the PMA serves as atemporary file management information recording area peculiar to theCD-R or CD-RW, the lead-in area serves as an intended area for writingfile management information or disc control information, called TOC(Table Of Contents), for use in a CD-ROM format, the lead-out area actsas an area for indicating the end of EFM data, and the program area actsas an area for recording user data. In the present invention, thisprogram area has both a read only area and rewritable area. To maintainthe readout compatibility with the conventional CD-ROMs, there is a needto record predetermined information in the lead-in and lead-out areas.

In the present invention, at least the area from the start point B ofthe PCA area to the end point D of the lead-out area (area indicated byoblique lines in FIG. 4( b)) is coated with the same phase change typemedium. More concretely, it has a multilayer structure described withreference to FIG. 3( a).

Thus, this optical recording medium is composed of a readable read onlyarea covered with a phase change type medium and has six layers, and aninformation rewritable area covered with the phase change type mediumand having the same multilayer structure as the six layers. Therewritable area has a wobbling guide groove 50 formed to guide laserlight as shown in FIG. 1( a).

As the areas for realizing a partial ROM function in the program area,there are two types: one is an area (master ROM area) in which data isrecorded using a pre-pits row (row of pits formed in advance) comprisingconcave 49 made previously in the substrate 110 f and the recordinglayer 110 e is placed on the substrate 110 f, and the other is an area(post ROM area) which, after data is recorded as a mark of the recordinglayer 110 d, inhibits re-write in a partial area thereof by a recordingdrive unit.

In a case in which only a rewritable area exists and only a post ROMarea exists as the ROM area, no pre-pit exists between the start point Bof the PCA area and the end point D of the lead-out area, but only theguide groove 50 is present. On the other hand, in the case of thepresence of the master area based on master ROM data, the pre-pits row52 and the guide groove 50 exist, and in this case, it is preferablethat the guide groove in a wide sense is continuously formed so that thecenter line 50 b of the pre-pits row 52 has a wobble showing the almostsame amplitude as that of the guide groove 50 as shown in FIG. 1( b).

In any case, since the address information is provided along the guidegroove in the wide sense in the range from the start point B of the PCAarea to the end point D of the lead-out area, it is preferable thataddress information expressed in terms of absolute time and a syncsignal are added by the guide groove (ATIP information, absolute time inpregroove). The absolute time address is determined so that 1/75 is setas the minimum unit (frame), and is expressed in units of minutes,seconds and frames. In FIG. 4( a), the ATIP starts at 0 minute 0 second0 frame (which will hereinafter be expressed in the form of “00:00:00”)at the start point A of the program area, and continues up to 79:59:74frame. In accordance with the data volume, the maximum ATIP address ofthe program area can vary. The program area shifts to the lead-out areaat the C point in FIG. 4( a). The ATIP address of the lead-out areaincreases continuously following the final ATIP address of the programarea. In general, the length of the lead-out area is approximately 1 to2 minutes. On the other hand, the PCA, PAM and lead-in area are locatedbetween the B point and the A point in FIG. 4( a). The ATIP addressthereof is reset to 00:00:00 at the A point, and then decreasessequentially from 99:59:74 in the direction from the A point to the Bpoint (first address of the PCA). The ATIP address of the PCA, PMA andlead-in are limited to the order of 80 or 90 minutes.

In the present invention, in the CD format, it is preferable that, ofthree data hierarchies of an ATIP frame, an EFM frame and a block unitof approximately 2 k bytes, a rewritable or read only attribution isprescribed in at least one hierarchy. This is because it is connectedwith the minimum unit capable of manipulating data in the CD-ROM systemand the definition of the data attribution becomes possible at lowerlevels.

In addition, preferably, there are provided the attribution on whetherit is rewritable, the attribution on whether it is non-rewritable(write-once or write-first-time) and the attribution on whether it isrepeatedly rewritable. That is, in the best mode, for at least one ofthe above-mentioned three hierarchies, there are provided at least threetypes of attributions of write inhibit (read only), write-one (firsttime) (which functions as the post ROM area after recording) and rewrite(repeatedly rewritable).

In this case, the write inhibit (read only) attribution inhibits theoverwrite on the master ROM or post ROM data and says handling as readonly data. The write-once attribution, aside from recording atformatting which will be described later, achieves the write-once of theuser data at an address, equipped with the aforesaid attribution, torealize a pseudo CD-R disc, and is effective to prevent the datafalsification in the CD-RW disc.

Still additionally, the type of attribution is not limited to thesethree types, but is also possible to set a conditional readout or aconditional rewrite according to applications. In this case, theconditional readout signifies, for example, data which can be read outonly when a predetermined cipher or the like is inputted. Likewise, theconditional rewrite signifies, for example, that recording is allowedonly in the case of input of a predetermined cipher.

Meanwhile, for the CD-RW, as methods of adding address data, there arethree hierarchies. This is related to the basic data unit prescribing agroup of data in a CD format. That is, since address is added accordingto basic unit of data, it is natural that the data attributioninformation is also added according to basic unit of address data, andit is preferable to make use of the redundancy of the addressinformation data bit.

As the address-added hierarchies, there are three hierarchies:

(1) an ATIP frame depending on a wobble;

(2) In an EFM signal, a subcode added to user data (for each 98 EFMframe); and

(3) a header of a block with a length of approximately 2 kB in a CD-ROMformat.

All of these correspond to 1 frame 1/75 seconds, forming a minimum unitof ATIP and are synchronized with an ATIP address forming an addressbasically fixed physically to a disc and, further, are described interms of in the same units of minute, second and frame. When viewed fromthe user data, it is partitioned into block units (2352 bytes) of theCD-ROM format, and in the course of the EFM, a subcode is added theretoso that an EFM signal is recorded at a predetermined ATIP address withthis address corresponding in position to the ATIP address.

First, in the following (A1), (A2) and (A3), a detailed description willbe given of data attribution adding methods in three hierarchies of theabove-mentioned wobble ATIP signal, EFM signal subcode and CD-ROM formatblock structure. The following description will be given by the use offormats and terminology for CD and CD-RW.

(A1) Method Using ATIP Frame on Wobble

This method is a method taken on the lowest-order hierarchy, and is forprescribing a read only area or a write-once area through the use of aconfiguration made previously on a substrate, concretely, it utilizesATIP information written in a wobble.

The ATIP information takes 1/75 second as the minimum unit (frame) of anaddress and assumes 22.05 kHz as a spatial frequency of a wobble, withone frame including a wobble of 294 periods. In addition, one frameincludes information of 42 bits and, therefore, every seven periodscorrespond to one bit. That is, frequency-modulation (FM) of ±1 kHz ismade at every seven periods according to whether the data is “0” or “1”.A sync bit for decoding the data, together with absolute timeinformation and error correction information accompanied therewith, isincluded in the 42 bits of the ATIP information.

FIG. 5 is an illustration of an ATIP data structure. In FIG. 5, each ofthree types of bytes 22 a, 22 b and 22 c is produced by decoding awobble frequency-modulated. The byte 22 a represents minute information,the byte 22 b denotes second information, and the byte 22 c signifiesframe information. In addition, the unit of each of the minute, secondand frame ( 1/75 second) is expressed in terms of two-digits BCD (BinaryCoded Decimal) and, hence, the ATIP information is represented with fourbits for each place, i.e., eight bits (one byte) in total. Stilladditionally, (M1, S1, F1) forming the most significant bits of therespective bytes 22 a, 22 b and 22 c are put to use.

A description will be given hereinbelow of a mode utilizing the (M1, S1,F1).

In the prescription for compact discs, the value of ATIP information ina program area is from 00 minute 00 second 00 frame to, at most, 79minute 59 second 74 frame, so data equivalent to the order of 80 or 90minutes in BCD does not appear in the intended program area. That is, inFIG. 5, “1” does not appear at any bit of M1, S1 and F1 forming the MSB(Most Significant Bit) of each unit. In the lead-in area of the CD-RWdisc, when “1” appears in S1 to F1, special information such as discrecording condition is written positively through the use of a lowerbits.

In particular, when “1” appears at the M1 bit forming the MSB of theminute unit, although it can be mistaken for the lead-in, PCA, PMA orlead-out area because of data exceeding 80 or 90 minutes, in the recentyears, in most cases, the program area has been allocated to near 79minute 59 second 74 frame and data exceeding 80 has been assigned to thelead-out, and hence the ATIP address of the lead-out area has notparticularly been distinguished from the ATIP address of the data area.On the other hand, commonly, the address exceeding 80 minutes has beenallocated to the PCA, PMA and the lead-in area. That is, only in thecase of M1=1, a decision can be made to an address other than theprogram area and the lead-out area. In addition, since a start addressof the lead-out is written in terms of absolute time in a part of filemanagement information stated in the lead-in area, it is possible todistinguish between the program area and the lead-out area on the basisof this information.

Meanwhile, in the program area, it is obvious that (M1, S1, F1)=(0, 0,0) only. This is because, since the second unit takes up to 59 seconds,“1000” and “1001” corresponding to “8” and “9” of ten digits of the BCDdo not appear, and since the frame unit takes up to 74 frames, likewise,“1000” and “1001” corresponding to “8” and “9” of ten digits of the BCDdo not appear. In a narrow sense, only in the case of (M1, S1, F1)=(0,0, 0), it can be considered as the program area.

Thus, in the program area, it is possible that a combination (M1, S1,F1)=(0, 0, 1), (0, 1, 0), (0, 1, 1) of M1, S1 and F1 bits is used asattribution information of the corresponding ATIP frame and the absolutetime of the ATIP frame is written by a lower digit bit.

So far, the combination (M1, S1, F1)=(0, 0, 1), (0, 1, 0), (0, 1, 1) hasbeen allocated to special information present in only the lead-in area.That is, if the ATIP information starting at M1=0 exists in the lead-inarea which takes only M1=1 as the absolute time, interpretation is madesuch that special information (recommendation recording condition or thelike) but the absolute time is written at the remaining bits.

The present invention proposes that, in the program area, special (M1,S1, F1) combination, which has not been defined so far, is allocated toattribution information of an ATIP frame, which provides a satisfactorymanner usable without significantly impairing the compatibility with theconventional devices.

First of all, a decision on a program area is made on the basis of M1=1and lead-out start time information written in the lead-in area, and ifMSB=(M1, S1, F1)=(0, 0, 0), a decision is made that data correspondingto the ATIP frame thereof is the conventional rewritable data. If (0, 0,1), (0, 1, 0), (0, 1, 1), the definition of the ATIP frame attributionbecomes possible. Since, irrespective of M1, S1 and F1 of MSB, anarbitrary ATIP address from 00:00:00 to 79:59:74 is expressible with thelower three bits of ten digits of the BCD and four bits of one digitthereof, no problem arises in adding address.

In the present invention, aside from association with (M1, S1, F1)=(0,0, 1), (0, 1, 0), (0, 1, 1), there are allocated at least three types ofattributions: inhibit of write (read only) based on pre-pits, write-once(first-time writable) (which functions as a post ROM area after therecording) and rewrite (repeatedly rewritable).

Incidentally, in order to add the above-mentioned ATIP information topre-pits, the center line 50 b of the pre-pits row 52 may be wobbled toshow the same amplitude as that of the rewritable area as shown in FIG.1( b). From a push-pull signal by pre-pits, it is possible to read out awobble signal and ATIP information easily just like a wobble signalbased on a wobble, and there is no need to use a special circuit.

FIG. 6 is a flow chart showing file write utilizing the ATIP. First, anoptical head is shifted to a predetermined address (step A1) to decodethe ATIP (step A2). Subsequently, at a step A3, a decision is made as towhether or not it arrives at a specified address. If the decision showsno arrival at the specified address, a NO route is taken to repeat theprocessing from the step A1. On the other hand, in the case of thearrival at the specified address, an YES route is taken, and at a stepA5, a decision is made on (M1, S1, F1).

In addition, a step A5 is implemented to make a decision as to anattribution of the ATIP frame on the basis of (M1, S1, F1). At thistime, if the attribution is the write inhibit, a write inhibit route isselected, and at a step A6, a decision is made to the read onlyattribution, and at a step A7, an error message is sent out, thenfollowed by a step A8 where the optical head is shifted to anotheraddress, thus repeating the processing from the step A1.

Furthermore, at the step A5, in the case of the “rewritable”, a“rewritable” route is selected, and a step A9, a decision is made to therewritable attribution and at a step A10, the writing starts, thenfollowed by a step A11 where the write routine comes to an end.

In this connection, in the flow chart of FIG. 6, although, after thestep A7 for sending out the error message, the step A9 is placed to movethe optical head to another address, it is also possible that theoperation terminates at the step A7 of sending out the error message.

As described above, since the write inhibit attribution is recorded inan ATIP signal, when having access to a predetermined address, therecording drive unit always decodes the ATIP address, and when detectingthe above-mentioned MSB combination, it immediately conducts theprocessing such as to stop the power of recording laser light forshifting to an abnormality processing routine. In addition, when therecording drive unit has access to a ROM area with a write inhibitattribution, an error message occurs at the write. Therefore, even ifthe recording drive unit designates an address in the inhibit area inerror, the destruction of the ROM data due to the mistaken writing ispreventable.

Even if the attribution of the ATIP frame in the program area is any oneof the attributions prescribed above, when the absolute time informationas usual is recorded in the form of subcode in the corresponding EFMsignal, the above-mentioned irregular M1-bit using method does notreflect on the EFM signal readout system. That is, the program area isset as M1=0 and the BCD data is produced according to only absolute timeinformation so that it is set as the absolute time information includedin a subcode of an EFM signal.

In this case, in general, the readout system side including the CD-ROMdrive acquires address information from only the subcode recorded withan EFM signal, which eliminates the influence of the allocation of theaforesaid irregular ATIP information from the readout system. Inaddition, this does not affect the readout by the existing CD-ROM drive.Although there is a need to alter the firmware (internal program fordrive control) only on the recording system side, this alteration isachievable simply by rewriting the program as the version-up of thedevice driver on the recording unit side, and the alteration of thehardware in the recording drive is unnecessary, so it is a preferableone.

Thus, in a P-ROM using a phase change type medium, logical seamless filemanagement of a ROM area and RAM area mixed becomes feasible through theuse of bit values of (M1, S1, F1).

In addition, since the access becomes possible with the same circuit inthis way, it is possible to efficiently realize both the datadistribution function and user data recording function, thus promotingthe utilization of a CD-RW disc.

A master ROM area is producible by a pre-pits row to which the writeinhibit (read only) attribution is added with the ATIP, thus ensuringthe write inhibit processing. On the other hand, if the write inhibit(read only) attribution is given to a part of a non-recorded rewritablearea in the case of the ATIP and data is recorded and edited by only afactory or software manufacturer through the use of a special recordingdrive unit which can ignore the write inhibit processing, the recordingdrive unit for general users can create a post ROM area functioning asROM data. In addition, the rewritable attribution is given to only theremaining rewritable area so that it is maintained in a state usable asa RAM area on the user side.

Since the attribution based on the ATIP is given to a wide-sense wobbleformed previously on a substrate, the rewrite of the attribution itselfbecomes impossible, thus providing a highest-reliability ROM datafalsification preventing method.

Thus, three types of data areas: a master ROM, a post ROM and a RAM, canbe mixed on the same disc.

In addition, the rewritable area to which the write-once (first-timewritable) attribution is added according to the ATIP is usable as apseudo write-one medium on the user side and a master ROM area isproducible on the user side.

(A2) Method of Using Subcode (for Each 98 EFM Frame) Added to User Datain EFM Signal

FIG. 7 is an illustration of a block comprising 98 frames (sectors)arranged. In FIG. 7, a block 23 has a sync signal (12 bytes) indicativeof a block head and a header (4 bytes) including writable/non-writableinformation on addresses or the like. In addition, the recording driveunit is designed to add auxiliary data (288 bytes) for error correctionto the original data on user data and, after these data are scrambled,divides into 24 bytes×98 lines for adding error correction parity bit, asubcode and others to each line, thereby performing the EFM modulation.Each of these lines is referred to as a “EFM frame”.

In the case of an audio format (CD-DA) prescribed in the Red Book, aframe unit ( 1/75-second length) forming a minimum unit of the ATIPincludes user data of 2352-bytes length. The user data of the 2352-byteslength is called a main channel, and is divided into a 24-bytes for oneline×98-lines matrix. When each line is divided in units of 12 bytes, itbecomes data corresponding to the right and left channels of stereomusic data. After an additional bit for error correction is furtheradded to each line, an 8-bit data called a subcode is added. That is,through the use of 8-bit×98 auxiliary data, addresses and dataattribution information are added to a block made in units of 2352bytes. The header information of the aforesaid block is data-processedat an IC level of a lower level, in addition to the CD-ROM drive, amusic CD drive can also give a recognizable data attribution.

A 98-line matrix is established in a state where eight bits of thesubcode is set as one line, and a data string of 98 bits (12 bytes) setby grouping each string is referred to as a “channel”, and named P, Q,R, S, T, U, V or W channel. In particular, one of these is referred toas a “Q channel”, and the address information is described in 98 bits ofthe Q channel.

Since the subcode includes 8×98 bits, many non-used bits exist, so newdata attributions can be added using the non-used bits. A descriptionwill be given hereinbelow of an example in which the control bit is usedutilizing the Q channel.

FIG. 8 is an illustration of a data structure of the Q channel. In FIG.8, Q channel data 24 includes sync bits (S0, S1), a control bit(CONTROL), and other data bits. The control bit (CONTROL) isrepresentative of a write attribution, and is composed of (SC3, SC2,SC1, SC0) in the order of rank lowering.

More concretely, the four bits (SC3, SC2, SC1, SC0) of the CONTROL fieldof the subcode Q channel shown in FIG. 8 are used as follows. That is,according to the contents disclosed in Japanese Laid-Open (Kokai) No.HEI 11-250522, the four bits of the CONTROL bit are specified as shownin the Table 1 in the Red Book/Yellow Book. In the Table 1, mark xrepresents that any one of “0” and “1” is acceptable, and theprescription on the item numbers 1 to 6 has already been used in thecurrent standards.

TABLE 1 Allocation of CONTROL Bit Item Description of Data No SC3, SC2,SC1, SC0 Attribution Specified 1 0, 0, x, 0 two audio channels with nopre-emphasis 2 0, 0, x, 1 two audio channel with pre- emphasis 3 0, 1,x, 0 data track recorded in Track at Once 4 0, 1, x, 1 data trackrecorded in recordable mode 5 x, x, 0, 1 digital copy inhibit 6 x, x, 1,x, digital copy permission 7 1, 0, x, 0 non-defined 8 1, 0, x, 1non-defined 9 1, 1, x, 0 non-defined 10 1, 1, x, 1 non-defined

In this Table, each of the item numbers 1 and 2 relates to theattribution of an audio signal. In addition, as found from the itemnumbers 5 and 6, irrespective of other attributions of data, the SC1 bitis allocated to the specification of digital copy inhibition/permission,and cannot be put to use.

In consequence, at present, spare (non-defined) is set up in a case inwhich SC2 to SC0 assume “0” or “1” only when SC3=1 cases as the items 7,8, 9 and 10, and the data track write inhibit (read only) attributionsare defined utilizing these combinations.

That is, in this method, when SC3=1, it is considered as a data track ofa CD-ROM format, and only in this case, the write inhibit (read only)attribution can be defined a combination of SC2 and SC0.

Therefore, when SC3=1, possible combinations (0, 0), (0, 1), (1, 0) and(1, 1) of (SC2, SC0) are allocated to at least three types ofattributions: the write inhibit (read only), write-once (first-timewritable) (which functions as a post ROM area after the recording), andrewrite (repeatedly rewritable). In addition, with respect to which ofthe attributions is one of the (SC2, SC0) combinations, free selectionis possible. Still additionally, it is also possible that three of (0,0), (0, 1), (1, 0) and (1, 1) are allocated to the attributions and theremaining one is given to, for example, a conditional readout orwritable attribution.

With respect to the subcode, including the other channels, all non-usedbit assigns can be an object of the allocation of data attributions, butthe channels R to W are employed for a maximum of 64 applicationprescriptions (CD-G, CD-TEXT, and others); for this reason, it ispreferable to use a method utilizing a block attribution limited to theATIP described in (A1) or to a CD-ROM format to be described in (A3).

FIG. 9 is a flow chart showing file write utilizing an EFM signal.

First of all, an optical head is shifted to a predetermined address(step B1) to perform ATIP decoding (step B2). Subsequently, at a stepB3, a decision is made as to whether or not it arrives at a specifiedaddress. If the specified address is not reached, a NO route is taken torepeatedly conduct the processing from the step B1. On the other hand,for the arrival at the specified address, an YES rout is taken to decodethe EFM signal at a step B4.

Following this, at a step B5, a decision on attribution is made on thebasis of the data of the Q channel decoded. If the decision attributionis the write inhibit attribution, a write inhibit route is selected tomake a decision to the read only attribution at a step B6 and send outan error message at a step B7, then followed by a step B8 to shift theoptical head to another address, thereafter repeatedly conducting theprocessing from the step B1.

In addition, if the step B5 shows the rewritable attribution, the“rewritable” route is selected to make a decision to the rewritableattribution at a step B9 and start the writing at a step B10, thenfollowed by a step B11 to terminate the write routine.

Incidentally, in the above-mentioned flow chart of FIG. 9, although thestep B8 for shifting the optical head to another address is placed afterthe step B7 for sending out the error message, it is also possible toterminate the routine at the step B7 to send an error message.

Thus, since data processing is conducted at the IC level of a lowerlevel unlike header information of a block which will be describedlater, in addition to the CD-ROM drive, a music CD drive can also give arecognizable data attribution.

In addition, in this way, since the recording drive unit side can copewith it only by rewriting the program through the version-up of a devicedriver incorporated into a firmware, it is possible to eliminate theneed for the alteration of the hardware of the recording drive unit andfurther to handle it in an existing unit used condition. Incidentally,also on the readout side, in a case in which an error takes place forthat another bit is put in a (SC2, SC0) bit in which (0, 0) data hasusually been placed in a non-defined state so far, there may be a needto rewrite the firmware.

Still additionally, logical seamless file management can be implementedthrough the use of the control bit (SC2, SC0) of the Q channel, so a ROMarea and a RAM area can be placed in a mixed state on the same phasechange type medium.

Moreover, in this way, since the access is made through the use of thesame readout circuit, it is possible to efficiently realize a datadistribution function and a user data recording function, which promotesthe use of the CD-RW disc.

Still moreover, after predetermined data editing recording is made in apart of the rewritable area on the factory or software manufacturerside, the data is defined as the write inhibit (read only) using asubcode attached thereto, the actual master ROM area is producible. Ifthe data write inhibit attribution in the rewritable is set so that analteration thereof is inhibited on the user side, it is possible toprevent it from being falsified against the intention of the post ROMdata manufacturer.

Naturally, for the master ROM area comprising a pre-pits row, the writeinhibit (read only) attribution is given to the subcode in producingpre-pits row data. In addition, the rewritable attribution is given toonly the remaining rewritable area so that it is usable as a RAM area onthe user side.

Thus, three data areas of master ROM, post ROM and RAM can be placed ina mixed state on the same disc.

(A3) Method of Using Header of Block with Length of Approximately 2 kBin CD-ROM Format

In this embodiment, data attributions such as read only and writeinhibit are given in units of blocks prescribed in a CD-ROM format. Asstated above, in the CD-ROM format, user data is partitioned accordingto 2048 bytes, and auxiliary data is added to this 2048-byte data toproduce data equivalent to one block (2352 bytes).

That is, a block 23 (see FIG. 7) is composed of a sync signal (12 bytes)indicative of the head of a block and a header (4 bytes) including“writable”/“non-writable” information such as addresses, and auxiliarydata (288 bytes) for error correction is further added thereto. Thesedata except the sync signal are scrambled. In addition, the datacomprising the sync signal and the scrambled data is divided into 24bytes×98 lines, and parity bits for error correction, a subcodedescribed in (A2) and others are added to each line, and modulated inEFM.

In addition, each block has a header, and auxiliary data indicative ofan address of each block, data attribution and others is added to eachheader. This header data comprises four bytes, and through three ofthese bytes, the address of each block is recorded with 24 bits in unitsof minute, second and frame identical to those in the ATIP (see FIG. 5).

Still additionally, through the use of the remaining one byte (8 bits),attribution data indicative of a mode of each block is added to eachheader. In the Orange Book Part 3, an attribution of the block isprescribed in order to use the packet recording which will be describedlater, and is recorded with specified three bits. Moreover, specificinformation prescribed in the Yellow Book is added with different twobits. The remaining three bits are free bits which are not prescribedparticularly.

That is, with respect to these three free bits, there are provided atleast three types of attributions: the writable attribution, the writeinhibit (read only) attribution and the write-once (first-time writable)attribution on that block. In addition, when provided, three types ofstates are simply given, only two bits will work in fact, and freeselection of one of the three bits becomes possible.

For example, assuming that these three bits are (b2, b1, b0), of thesebits, (b1, b0) are allocated to one of three types of attributions: therewritable attribution, the write inhibit (read only) attribution andthe write-once (first-time writable) attribution according as (0, 0),(0, 1), (1, 0) or (1, 1). This allocation can be made through freeselection. In addition, since it is possible to give eight types ofattributions by the use of all of the three bits, a conditional readableattribution or a conditional rewritable attribution can also be anobject of the allocation.

Thus, the “rewritable”/“non-rewritable” attribution can be given inunits of blocks to the user data of the CD-ROM format.

Meanwhile, for the CD-RW, a method called fixed-length packet recordingis used for allowing data to be rewritten at an arbitrary address.

FIG. 10 is an illustration of a packet structure in the fixed-lengthpacket recording. In FIG. 10, a packet 25 forms a data recording unit ina fixed-length packet recording mode for the CD-RW, and this packet 25is composed of a link block 25 a, run-in blocks 25 b, . . . , 25 c, userdata blocks 26 a, . . . , 26 b, and run-out blocks 27 a, 27 b. The linkblock 25 a serves as a buffer area for preventing data destruction ofthe existing adjacent packet stemming from positional shifts ofoverwritten data. Each of the run-in blocks 25 b, . . . , 25 c and therun-out block 27 a acts as an area for accommodating additionalinformation to be added to the user data. Incidentally, the packetsignifies a minimum group of data equally called a sector or cluster.

In this case, these plurality of blocks are grouped (one packet) and areoverwritten according to packet. In addition, the user data shown inFIG. 10 is recorded in the form of packet with a unit of 64 k bytes (32blocks). The description of these blocks will be omitted because ofbeing described in the Orange Book Part 3. Moreover, the file managementmethod for the fixed-length packet recording is prescribed in the UDFversion 1.5 which will be mentioned later.

Furthermore, at the shipment from a factory, the packet structure shownin FIG. 10 is recorded on the overall surface of a disc through anoperation called full formatting. At this time, for handling thefixed-length packet recording, the recording of any user data isacceptable, but in fact, “0” data is recorded. In addition, with respectto a formatted disc (disc formatted in a factory), meaningless data isrecorded in the user data blocks 26 a, . . . , 26 b shown in FIG. 10,and when the user records and uses the user data, a fixed-length packetis overwritten in a state where the link blocks 25 a of two packetsadjacent to each other are set as a start point and an end point,respectively.

Still furthermore, of one byte of the above-mentioned header, three bitsspecified are made to indicate which of the link block, the run-inblock, the user data block and the run-out block each block performs to.

Incidentally, in the formatted disc, it is also possible that, forproducing a post ROM area, in place of the recording of the dummy “0”data at formatting, meaningful data is recorded and an attribution foreach of the aforesaid data blocks is set as the write inhibit (readonly) attribution.

Moreover, even in a case in which data is recorded in the form of apre-pits row according to the fixed-length packet recording format toproduce a master ROM area, if an attribution for each of the data blocksis set as the write inhibit (read only) attribution, then the overwriteon the master ROM area is preventable.

In this way, the three types of data areas: a master ROM, a post ROM anda RAM can be placed in a mixed state on the same disc.

Still moreover, in the formatted disc, by giving an attribution for eachblock, a rewritable area equipped with the write-once (first-timewritable) attribution can thereafter be used as a pseudo write-oncemedium, so the user side can create a master ROM area.

When a data attribution is given for each block forming a basic unit ofdata in the CD-ROM format as described above, the recording drive unitfor the CD-RW disc 10 can make a correct decision on the “write inhibit”and others through the above-described operations. That is, in therecording drive unit for the CD-RW disc 10, packet data to be recordedis first read out to rewrite the data of a given block of the packet ina memory of the drive for organizing the data in the packet and then thepacket on the recording medium is rewritten actually.

In this case, when the data of the packet to be recorded is read out,the attribution of the block is decoded, and if a write inhibit (readonly) block exists in the packet, an error message describing thisexistence is issued.

FIG. 11 is a flow chart showing file write utilizing block attributions.First, an optical head is shifted to a predetermined address (step C1)for performing the decoding of the ATIP (step C2). Subsequently, at astep C3, a decision is made as to whether or not it arrives at aspecified address. If the specified address is not reached, a NO routeis taken to repeatedly conduct the processing from the step C1. On theother hand, in the case of the arrival at the specified address, an YESroute is taken, so an EFM signal is decoded at a step C4.

Following this, a signal is decoded in units of blocks at a step C5, anda decision on block attribution is made at a step C6.

If the block attribution is the write inhibit attribution, a writeinhibit route is selected to make a decision to the read onlyattribution at a step C7 and send out an error message at a step C8,then followed by a step C9 where the optical head is shifted to anotheraddress for repeatedly conducting the processing from the step C1.

In addition, if the step C6 shows the rewritable attribution, the“rewritable” route is selected to make a decision to the rewritableattribution at a step C10 and start the writing at a step C11, thenfollowed by a step C12 where the write routine terminates.

Incidentally, in the above-mentioned flow chart of FIG. 11, although thestep C9 for shifting the optical head to another address is placed afterthe step C8 for sending out the error message, it is also possible thatthe routine terminates at the error message sending step C8.

As described above, a data attribution is given for each block forming abasic unit of data in the CD format, thus making a correct decision onthe “write inhibit” and others. In addition, except for the overallerase, the recording drive unit can overwrite data in units of packetsin a state where the link block 25 a is used as the start point and endpoint.

Viewing the purpose of the use thereof, it is preferable that theattribution of a link block, particularly, a link block at a junctionbetween a ROM area and a RAM area is set to the “rewritable”.

In addition, only by rewriting a device driver incorporated into thefirmware without altering the hardware on the recording drive unit side,it is possible to provide a CD-RW disc 10 with a phase change typemedium where a RAM area and a ROM area are placed in a mixed state.

In this way, the access can be made with the same readout circuit and,therefore, it is possible to efficiently realize the data distributionfunction and the user data recording function, thereby promoting the useof the CD-RW disc.

The above-described three types of modes relate to methods in which anew attribution is added to data of each address basic unit according toaddress giving hierarchy, and the method itself which adds dataattributions in units of address uses a method capable of maintainingthe compatibility with the CD format.

In this case, in two or more hierarchies, in a case in which a dataattribution is given to the same address basic unit, it is preferablethat the data to be given in the higher hierarchy is the same as theattribution of the data to be given in the lower hierarchy.

Secondly, a brief description will be given of an example in which adata attribution is given to a variable-length basic data unit.

As examples of variable-length data units in the CD format, there are atrack and a session in a multisession format. In addition, in thefixed-length packet recording format prescribed in the UDF1.5, a dataunit using a plurality of fixed-length packets sequentially is also oneexample of the variable-length data unit.

In the CD-ROM format, the track corresponds substantially to a case inwhich the number of blocks is not fixed with respect to the group ofuser data blocks 26 a, . . . , 26 b shown in FIG. 10. Accordingly, aswell as the fixed-length packets, it is possible that a data attributionsuch as “write inhibit” is given to each block belonging to the track.

On the other hand, a data attribution on the track per se is given to aheader of a leading run-in block of the track. The write inhibit (readonly) attribution, the write-once (first-time writable) attribution orthe rewritable attribution can be given in units of tracks through theuse of free bits thereof.

Moreover, the start and end addresses of a track, the data length andothers are written as TOC at a subcode Q channel of an EFM signal in thelead-in area. At this time, it is preferable to describe each trackattribution. Still moreover, when needed, that track attribution can beput in the user data (main channel) equipped with the subcode Q channel.Only dummy data usually taking “zero” is written in the main channel (auser data portion in the block structure shown in FIG. 7) of the EFMsignal in the lead-in area, and therefore, there is no problem whenauxiliary data is written in that main channel, and the recording driveunit reads out not only the subcode but also the main channel even inthe lead-in area.

In particular, the address information (start and end addresses, datalength, and others) of a track has a read only area attributionexpressed with master ROM data comprising a pre-pits row and, hence, canalso be written (registered) as master ROM data, likewise comprising apre-pits row, in the address main channel of a part of the lead-in area.

Furthermore, in the fixed-length packet recording format, in a case inwhich variable-length comprising a plurality of sequential packets ismaster ROM data comprising a pre-pits row, the address information ofthe sequential packets is written (registered) as mater ROM data in themain channel of the lead-in area.

Concretely, as the start address, there is used the address of the firstrun-in block of the leading packet or the address of the first user datablock of the leading packet. In addition, as the end address, there isused the address of the rear-end run-out block or the address of therear-end user data block. Furthermore, in the fixed-length packetrecording format, the addresses of the run-in, run-out and link blocksare skipped (the addresses are not put to use), and new addresses areallocated in order to only the user data blocks.

Moreover, a high-level logical address is also available. Payingattention to this logical address, the logical address of the leadinguser data block can also be used as the start address of that ROM area,while the logical address of the rearmost-end block can also be used asthe end address of that ROM area.

In addition, a description will be given of a method of dividing aprogram area according to a prescription of a multisession format into aplurality of sessions for setting a portion of divided sessions as theread only sessions and setting the remaining sessions as the rewritablesessions. Concretely, in a multisession disc, in the case of a P-ROM inwhich specified sessions are set as the write inhibit (read only)sessions, it is preferable that an attribution representative of whethereach session is the write inhibit (read only) session or the rewritablesession is written in the lead-in of that session. For this purpose, theQ channel of the subcode is likewise put to use.

That is, in the multisession format, one CD including the lead-inarea/program area/lead-out area shown in FIG. 4( a) is divided toconstruct a plurality of pseudo CDs on the same CD.

FIG. 13 is an illustration for explaining an example of an areaconfiguration of a CD having a multisession format which is partitionedinto three sessions. In each session, its head section is equipped witha lead-in area while its rear end section is equipped with a lead-outarea. In FIG. 13, a lead-in area L₁A of a first session indicated on astraight line written obliquely on the right side corresponds to thelead-in area shown in FIG. 4( a). In addition, AL₂ represents a programarea of the first session, and L₂A₂ designates a lead-out area of thefirst session. Still additionally, A₂L₃, L₃L₄ and L₄A₃ denote a lead-outarea, program area and lead-out area in a second session, respectively,while A₃L₅, L₅C and CD depict a lead-in area, program area and lead-outarea in a third session, respectively. The PCA area and the PMA area areplaced at the innermost circumference BL₁ of the entire disc as well asthe case shown in FIG. 4( a).

Moreover, the data structure of each lead-in area is the same as that ofthe program area, and the subcode is likewise added thereto. In thelead-in area, the user data is dummy, and only the subcode informationis used for the purpose of the control of the system. Still moreover, inthe case of the fixed packet recording, in addition to the program area,the lead-in area and the lead-out area are also formatted with thepacket structure shown in FIG. 10.

The structure of the subcode Q channel is identical to the structureshown in FIG. 8, the file management information of each session, thesession attribution information and others are additionally written atthe low-order 92 bits.

A description will be given hereinbelow of methods of giving anattribution utilizing the subcode Q channel, that is, methods (1) and(2) of giving attributions such as the read only attribution, thewrite-once attribution and the arbitrarily rewritable attribution. Inthese methods, it is necessary that all the attributions defined are thesame in the data included in one session.

(1) Method MS1

Four bits of a CONTROL bit similar to those shown in FIG. 8 exist in thesubcode Q channel of the lead-in area. The method described above in(A2) is directly applicable. That is, according to the prescription, inthe same session, the data attribution defined by CONTROL needs to beconstant in principle, and as with the method described in (A2), for adata track of SC3=1, the rewritable or write inhibit (read only)attribution is defined according to a combination of (SC2, SC1).

(2) Method MS2

In the specification of the low-order 92 bits in FIG. 8, there are aplurality of non-used bit assigns, so a new session attribution can beprovided using any one of these bit assigns. As an example, when 2-bytedata called POINT is A0 (BCD), since a session format attribution iswritten by one byte called PSEC, the spare bit assign thereof is put touse. Session format attributions prescribed in the current Orange Bookrelate to the applications of CD data, and are only as follows.

00 (hexadecimal): CD-DA or CD-ROM (Yellow Book)

10: (hexadecimal): CD-i

20: (hexadecimal): CD-ROM-XA

Although a detailed description of each format will be omitted, in thepresent invention it can be defined as follows through the use of thelow-order data of 2-place data in hexadecimal, where x represents ahigh-order place in hexadecimal.

x0: rewritable session

x1: write inhibit (read only) session

x2: write-once (first-time writable) session

In this way, the rewritable, write inhibit (read only) and write-once(first-time writable) attributions can be defined according to session.Since the session is considered as a divided pseudo CD as mentionedabove, a plurality of virtual CDs different in data attribution fromeach other are realizable on one CD.

In this connection, in a case in which a rewritable/non-rewritableattribution is given according to session, it is not always necessary togive the attribution in units of smaller data as described in (A1), (A2)and (A3), but the simultaneous employment enhances the reliability.

A description will be given hereinbelow of a logical format of aROM/RAM-mixed P-ROM disc.

First, a CD-RW disc has a RAM area although partially, and the contentsof the user data area is rewritable, and for this reason, preferably,the lead-in area is designed to be rewritable. Since a PMA areatemporarily retains the file management information as well as thelead-in, RAM data is desirable. In addition, a trial write area PCA isalso required to exist in a RAM area in view of its nature.

It is desirable that the information indicative of the CD-RW being aP-ROM is included in the lead-in area to which the drive first hasaccess for acquiring information on the disc. In the present invention,when the file management information is written with RAM data, a simpleerase operation, which will be described later, prevents the filemanagement information in the ROM area from being erased unnecessarily,thereby preventing the presence of the ROM area from becomingunrecognizable. Usually, the lead-in area lies on the innercircumferential side with respect to the program area AC as indicated ABin FIG. 4( a). In a disc with the multisession format, the lead-inexists also in the program area AC, while the lead-in of the firstsession also exists on the inner circumferential side with respect tothe program area AC, and the information about the entire disc is placedin the lead-in of this session. In the following description, includinga case of single-session, unless otherwise specified particularly, thelead-in area of the first session will be referred to simply as a“lead-in area”.

In a non-recorded CD-RW disc, special information such as discattribution, recording condition or the like is placed in the lead-inarea on the basis of the ATIP having the data structure shown in FIG. 5.It is preferable that the information indicative of the CD-RW disc beinga P-ROM is first written therein. Although a plurality of possibilitiescan be considered from the current Orange Book Part 3, one concretemethod is prescribing in disc subtype information of data called specialinformation 1 in the ATIP. In FIG. 5, when (M1, S1, F1)=(1, 0, 1)appears in the lead-in area, the special information 1 is information tobe written with the remaining bits.

The subtype of the disc therein is prescribed with, of one byte (thebyte 22 c in FIG. 5) for describing frame information, three bits(indicated by XXX in FIG. 5) but F1 of four bits indicative of upperplaces in the BCD. In this case, eight prescription manners areavailable, but they are not determined at present, and it will bepossible to allocate the subtype of the CD-RW disc forming the P-ROMdisc in the future.

Meanwhile, in the case of a recorded CD-RW, usually, in the lead-inarea, such special information and closed session file managementinformation are also recorded with EFM data. Accordingly, it ispreferable that information indicative of the above-mentioned P-ROM isalso recorded with EFM data in the above-mentioned lead-in area.Concretely, it is placed in a subcode Q channel. The subcode Q channelhas the data structure shown in FIG. 8 even in the lead-in area, whilethe lead-in area has somewhat different contents of data to be recorded.In particular, in the case of the use of the above-mentioned ATIPspecial information 1, of the remaining 92 bits of the subcode Q channelshown in FIG. 8, the contents thereof are to be always recorded withspecified bits. Such recording in which the ATIP special information inthe lead-in area is duplicated into an EFM signal subcode has alreadybeen done in a CD-RW recording/readout drive unit put on the market.

In addition, in the case of the use of a P-ROM type CD-RW disc, in orderto recognize that the recording drive unit is for the P-ROM and toprevent the destruction of the file management information of ROM data,if a master ROM area based on pre-pits exists, it is preferable to writeit on the disc through the use of the ATIP special information.

On the other hand, in a case in which, as stated above, a write-onceattribution is given to the data in a RAM area through the ATIP, EFMsubcode and block attribution for using as a read only area after therecording, or in a case in which the write inhibit is established aftera plurality of times of rewriting so that a read only attribution isgiven to produce a post ROM area for a P-ROM, it is preferable thatinformation representative of the P-ROM is written in the lead-in areawith only EFM data. Concretely, the subtype information of a disc of theaforesaid subcode Q channel is recorded as a P-ROM attribution.

In the program area, on the design of drive, certain limitation isimposed on the utilization of the subcode to the prescription of thedata attributions constituting the object of the present invention, but,if anything, it is more preferable to use the subcode for theprescription of a subtype representative of the disc being a P-ROM inthe lead-in area lying at the innermost circumference, or for theprescription of an attribution for each session in the lead-in area ofeach session in the multisession format. For this reason, it ispositively available.

FIG. 14 is a flow chart for attribution decision according to session inthe case of the multisession, and is for describing an example of a flowchart in conducting file management according to session using a disc inwhich attribution information representative of the P-ROM is written inthe lead-in and, in the case of the multisession, a write attribution isprescribed according to session.

The processing starts at a step M0, and a step M1 follows to mount adisc in a recording/readout apparatus and set the focusing and trackingservo of a recording/readout optical head after a predetermined speed ofrotation is reached, thereby establishing the readout condition of thedisc. Usually, in this stage, the state that the disc is not CD, CD-ROMnor CD-R but is a CD-RW disc is recognized on the basis of informationsuch as reflectivity. Subsequently, at a step M2, the optical head hasaccess to the lead-in area, and at a step M3, it decodes specialinformation recorded with ATIP information or an EFM signal subcode inthe lead-in area to start acquiring a disc type and disc controlinformation such as a recommended recording condition.

Following this, a step M4 is executed to obtain the disc typeinformation, and to seize that the disc is of a P-ROM type and has aread only area from a portion of the special information, moreconcretely, for example, from the above-mentioned special information 1(see the description given with reference to FIG. 5). Then, at a stepM5, a decision is made as to whether or not the disc has multisession.

In this case, if the information obtained shows the P-ROM and themultisession, an YES route is taken so that the lead-in of therespective sessions are accessed sequentially at a step M6, dataattribution information written in the lead-in is obtained according tosession at a step M7, and at a step M8 there are acquired the startaddress and end address (start address of the lead-out) of a programarea in each session, the size of the session and, if the session is ina read only or recorded state, the file management information. Usually,the above-mentioned information are drawn in sequence from the sessionlocated at the inner circumferential side, and until the final sessionis confirmed at a step M9, a NO route is taken to repeatedly conduct theprocessing from the step M6 to the step M8.

Furthermore, in the case of single session, the NO route is taken at thestep M5, and the file management information in a program area isacquired at a step M10.

Incidentally, although this flow chart does not indicate a step inwhich, after the disc type or the attribution information of eachsession in the multisession are acquired, they are stored in a temporarystorage memory in the interior of the recording/readout apparatus, aswell as other disc control information, attribution information of eachsession or the like, they are commonly stored in the temporary storagememory on all such occasions, and the following operation of therecording/readout apparatus is not required to re-read the informationfrom the disc every time. In addition, a part of the controlinformation, particularly, the information such as the disc type,attribution of each session, size and address, are not only stored inthe temporary storage memory of the recording/readout apparatus but alsotransferred to a host computer connected to the recording/readoutapparatus to be stored in a memory of that host computer. They areemployed for application programs using the recording/readout apparatus,installed in the host computer side.

Moreover, when the attribution of each minimum session and the start/endaddress information is drawn from the lead-in area of each session, noproblem occurs in the simple erase which will be described later. Thereis no need to acquire the file management information in the programarea of each session, and it is also possible that the concrete filemanagement information is read out at the first time when the concretedata is recorded/read out.

Thereafter, an YES route is taken from the step M9 so that at a step M11the optical head has access to the PCA area, and at a step M12 anoptimum recording power is determined in a manner that a trial write ismade on the basis of the disc control information acquired in the stepM3, and further at a step M13 the processing enters a waiting stateuntil a concrete recording/readout command takes place.

Incidentally, it is also appropriate that the step M11 and the step M12are successively implemented immediately after the step M3, or that theyare executed after a concrete write start command is issued andimmediately before the shifting to the recording from the waiting statestep M13.

Meanwhile, for the CD-RW, there has been known a RAM data erase methodcalled a simple erase operation. This is an erase method of making afile disappear apparently from the readout drive unit by erasing thefile management information being the RAM data in the lead-in area orthe PMA area or by rewriting meaningless data (repetition of zero). Theexistence of a predetermined file can be erased without erasing thecontents of the file every time. Although the foregoing operation isconducted for each file or for each session in some cases, if theinformation at the innermost circumferential lead-in area in the disc iserased or rewritten, then the disc can apparently be used as acompletely non-recorded new disc, which provides convenience.

On the other hand, in a case in which a read only area is providedpartially like the present invention and even the file managementinformation on the files in the read only area is recorded as rewritabledata, there is a possibility that the foregoing simple erase operationerases the existence of the ROM data file in error to make furtheraccess difficult. In particular, although the contents of the file existin the master ROM, the access to the file can be difficult, whicheliminates the meaning of the formation of the master ROM area. Inaddition, there is a possibility that the data is overwritten withoutrecognizing the master ROM area as a ROM area.

For this reason, in the present invention, it is preferable to give awrite inhibit data attribution for preventing the erase of the ROM databy the direct overwrite, and further to take measures for the preventionfrom the erase of the ROM data stemming from the malfunctions in thesimple erase operation.

A concrete approach is shown in a flow chart of FIG. 15. FIG. 15 is aflow chart showing one example of a simple erase method for a P-ROM.First, when a simple erase instruction is issued at a step N0, a step N1follows to decode the special information recorded in the lead-in areaof the first session area, then followed by a step N2 to identify anddecide that the compact disc is of a rewritable type having a read onlyarea (identification step).

That is, that the disc is a rewritable type compact disc having a readonly area is recognized on the basis of the information in the lead-inarea of the leading session accessed initially.

In more detail, recognized is identification information previouslywritten in the form of pre-pits or a wobble on a substrate andrepresentative of a recording medium being a rewritable type includingpartially a read only area comprising a pre-pits row or a wobble(recognition step).

Following this at a step N3, attribution information is extracted andacquired from each of the lead-in areas of a plurality of sessions(extraction step), and at a step N4, a decision on an attribution aboutthe “rewritable” or “write inhibit” is made on the basis of theattribution information.

In addition, if the decision at the step N4 indicates the write inhibit(read only) attribution, an YES route is taken to, at a step N5, extractand acquire the file management information (file structure) in thatwrite inhibit session and transfer it to a temporary storage memory(memory transfer step). This file management information includes allthe information such as the start and end addresses of the ROM sessionand an address of a file written in a program area of the same session.Moreover, this step is repeatedly implemented until the last session isreached, and if a plurality of read only sessions exist, for each of thesessions, the file management information is acquired at the step N5 andis stored at the temporary storage memory. On the other hand, if thedecision at the step N4 does not indicate the write inhibit (read only)attribution, a NO route is selected to arrive at a step N6.

At the step N6, the confirmation of the attributions up to the lastsession comes to an end, an YES route is taken so that, at a step N7,the lead-in area of the leading (first) session and the PAM area areaccessed to erase all the file management information recorded in theseareas (erase step). Accordingly, regardless of the “read only” or the“rewritable”, all the files apparently disappear from the program areaso that the entire program area falls into a condition recognized as“non-recorded”. Incidentally, if that session is not the last session, aNO route is selected at the step N6 to repeatedly conduct the processingfrom the step N3.

Furthermore, at a step N8, the file management information (start/endaddress and others) of the write inhibit session transferred to theaforesaid temporary storage is re-registered in the lead-in area of theleading (first) session and the PMA area, and a step N10, the headaddress and recordable capacity of the rewritable area are updated(re-recording step), and then the processing comes to an end (step N11).

In this connection, in the case of a common CD-RW in which the disccomprises only a rewritable area, a NO route is selected at the step N2,and as well as the step N7, all the file management information in thelead-in and PMA areas are erased at a step N9, and further, the entirerecordable area is newly re-registered as the “rewritable” at a stepN10.

In this case, it is also possible that, as shown in FIG. 14, the stepsN1 to N6 are implemented at the first stage (see the step M1), in whichthe disc is mounted in the recording/readout apparatus, to previouslyacquire the necessary information and store it in the temporary storagememory and, at the simple erase, the information to be acquired in thesteps N1, N3 and N5 are obtained from the temporary storage memory whenthe simple erase instruction is issued at the step N0.

Accordingly, a data erase method for a rewritable phase change typerecording medium according to the present invention is concerned with arecording medium having a phase change type recording layer on itssubstrate and having a read only area and a rewritable area in aninformation recording area.

The data erase method comprises a recognition step of recognizingidentification information written in the form of pre-pits or a wobbleon the substrate and representative of a rewritable type includingpartially a read only area comprising a pre-pits row and a wobble, amemory transfer step of acquiring address information in the read onlyarea to transfer the address information to a storage unit, an erasestep of erasing file management information written in a file managementarea, and a re-recording step of recording, in the file management area,the address information of the read only area transferred to the storageunit.

Furthermore, a description will be given hereinbelow of a data formatfor each of the ROM and RAM areas.

First, data structures to be recorded in a program area are roughlyclassified into two types of an ISO9660 format and a fixed-length packetrecording format prescribed in the UDF (Universal Disc Format) version1.5.

The ISO9660 format is designed to determine a procedure related to filemanagement information for a CD-ROM (Yellow Book) intended for readonly, and hence, is not highly suitable for the writable type filemanagement. That is, it is made on the assumption that a specified fileis fixed on a disc and exists at a sequential addresses, and isunsuitable for data structures randomly accessible like a hard disc andrecorded in units of packet (a minimum group of data equally called asector or cluster). However, this is a format which has come intowidespread use and can be read out through a CD-ROM drive.

On the other hand, the UDF version 1.5 and multilead format (which willhereinafter be referred to simply as a “UDF format”) has been determinedby U.S. Business Group OSTA (Optical Storage Technology Association) asa subset of the international standard related to file structures,called ISO13340, and as a structure for fixed-length packet recording,there has commonly been employed a packet structure shown in FIG. 10.

This format particularly determines how to set file managementinformation on a randomly accessible CD-RW and a disc serving as anequivalent virtual logical device, and is prescribed in order tofacilitate control of files from a host computer and to ensure thecompatibility.

A detailed description will be given hereinbelow of a logical structureof a partial ROM compatible with hardware of the existing drive,firmware, CD-ROM of host computers, device drivers of CD-R/RW drive andfile formats of the UDF version 1.5.

That is, this relates to a medium with a logical structure in which aprogram area is divided into two sessions according to the prescriptionof the multisession format while the first session is used as a ROM areaand the second session is used as a RAM area, or the first session istaken as a RAM and the second session is taken as a ROM area.

In a disc having a plurality of sessions according to the multisessionformat in this way, in the case of a P-ROM in which a specified sessionis used as “read only”, in principle, it is preferable that all the filemanagement modes of the respective sessions are the same. That is, inthe current Orange Book, provided that the file management method ofeach of the sessions is standardized with the ISO9660 format or the UDFformat, the file management method is acceptable even if differencesoccurs among the sessions. This is because the different sessions can beconsidered as virtually separate discs. However, in the case of theP-ROM medium, as will be described later, an interactive application canbe considered where data of an application program is read out from asession forming a ROM to conduct predetermined processing in accordancewith the program for recording the result immediately in a sessionforming a RAM, and the access between the session serving as the ROM andthe session acting as the RAM can frequently be made forreadout/recording of data. In general, the use of a method ofeliminating the need for the switching of the file management modeaccording to switching between sessions is more preferable, for that thedevice driver becomes simple.

In addition, since the fixed-length packet recording of the UDF ispreferable in the rewritable area, it is preferable to perform the filemanagement in the UDF format in all the sessions.

However, it can be considered that, if anything, the use of differentfile management methods among the sessions is advantageous. One of thesemethods is that a device driver program capable of the file managementin the UDF is written as ROM data in the first session according to theISO9660 format and, when a disc is mounted in a recording/readoutapparatus, the device driver is read out to allow the read/write of datain the UDF format. It is fit for such a using method.

More concretely, the first session is made as a ROM area while thesecond session is made as a RAM area, and a structure shown in FIG. 12(a) is taken where the ROM area is used as the ISO9660 while the RAM areais used as a fixed-length packet recording area according to the UDFformat.

In a case in which the first session is set as the ISO9660 as shown inFIG. 12( a), the follow-up of the file management method of the ISO9660becomes easier, for that, in the case of the ISO9660, the informationabout a logical address 16 located in the leading portion of the programarea is obtainable. Incidentally, in general, the first address of thelogical addresses corresponds to one block length of a CD-ROM format.

In the arrangement shown in FIG. 12( a), the first session is a ROM areawhile the second session is a RAM area, and the first session recordedin the ISO9660 format while the second session is subjected to writingaccording to the UDF format (version 1.5). In addition, a lead-in areaand a lead-out area are provided at every session in accordance with theprescription of a writing mode based on the multisession mode. Stilladditionally, a start address of a non-recorded area subsequent to thesecond session forming the RAM area is recorded in the PMA.

The first session processed in this way is recognized as a closedsession, and is recognized as a non-rewritable read only area accordingto the multisession prescription. Accordingly, a ROM data attribution isgiven to the first session units of the above-mentioned ATIP frame,subcode or block, and if the first session is put in a closed condition,this signifies that the re-write inhibit processing is doubled on thesystem, thus enhancing the reliability on the prevention from the ROMdata destruction.

With such processing, the following data recording method becomespossible. That is, usually, after the access to the data attributioninformation in a read only area, there are conducted a transfer step inwhich program data recorded in a executable format in the read only areais transferred to an external computer and an execution step in whichthe program data is automatically executed in the external computer torecord data in a rewritable area.

FIG. 16 is a flow chart showing one example of an automatic execution ofROM data, and is an flow chart for explaining the automatic execution ina case in which a recording/readout apparatus is connected to a hostcomputer whose operating system is Windows (product name, produced byMicrosoft Corporation.

First, after a flow is implemented up to the step M12 in FIG. 14, thewaiting step M13 is set as a step P0 in FIG. 16 and file managementinformation in the first session forming a read only area is acquiredaccording to the procedure of the ISO9660 at a step P1. In the Windows,a route directory is retrieved at a step P2 and, if a file named“autorun.inf” exists, an YES route is taken so that the file istransferred to the host computer at a step P3 and a program with thecontents prescribed in the file are automatically started up at a stepP4 (execution step). In this case, if the “autorun.inf” points outanother executable format program files and uses it, the files pointedout are successively transferred to the host computer to be put inexecution. At a step P5, the execution of a series of programs comes toan end, and the flow returns to the step P0. If the file named“autorun.inf” does not exist in the route directory, the flow returns tothe step M13 in FIG. 14 and enters the waiting condition. If the filenamed “autorun.inf” is absent at the step P2, a NO route is taken torepeatedly conduct the processing from the step P0.

At present, the ISO9660 is important in maintaining the compatibilitywith a CD-ROM constituting an optical disc system which has come intothe most widespread use and has been put on the market in a state almost100%-contained in a computer. In particular, in the case of a bootableprogram whereby data of a ROM area is automatically read out by a hostcomputer and implemented therein, the complete compatibility with theexisting formats becomes necessary. In addition, it can be considered toemploy a using method in which a device driver (and a program forinstalling it) which handles the UDF format which has not been widelyspread is recorded as ROM data according to the ISO9660 formataccessible from a common CD-ROM device driver and the program is read onthe host computer to install the UDF device driver.

In an arrangement shown in FIG. 12( b), the first session serves as aRAM area in the UDF format while the second session acts as a ROM areain the ISO9660. In FIG. 12( b), a using method in which a conditionalreadout-permissible attribution is given to data in the second sessionis particularly useful that. That is, a recording drive unit writes userdata only in the RAM area of the first session while a user cannot gainaccess to the second session, and only when inputting specified cipherinformation or the like, the user reads out the ROM information in thesecond session. Thus, since an area rewritable only by a desired user isprovided, the handling becomes easy.

In any case, for the session of the ISO9660 format, all the blocks ofthe lead-in/lead-out and program area are made as user data blocks. Inaddition, for the session of the UDF format, a link block, run-inblocks, user data blocks and run-out blocks shown in FIG. 10 are formedin the lead-in/lead-out and program areas.

Furthermore, as shown in FIG. 12( a), (b), a program area is dividedinto two sessions according to the prescription of the multisessionformat, and the session used as a RAM area is collectively used as afixed-length packet recording area according to the UDF format, whichimproves the convenience.

On the other hand, in some cases, it is preferable that the switchingbetween the device drivers handling the ISO9660 and the UDF respectivelyis unnecessary. If the UDF handling device driver further comes intowidespread use, for the CD-RW, it is preferable to control all theprogram area through the use of the UDF format. In this case, the layoutshown in FIG. 12( c) or (d) is suitable. The layout shown in FIG. 12( c)is formatted to conduct the fixed-length packet recording of the UDF ina single session, with the switching between the ROM area and the RAMarea being made through the link block shown in FIG. 10. In addition,the layout shown in FIG. 12( d) is a multisession format comprising twosessions, with one being used as a ROM area and the other being used asa RAM area. Both are formatted as shown in FIG. 10 so as to conduct thefixed-length packet recording of the UDF.

In the case of the layout shown in FIG. 12( c) and FIG. 12( d), it ispreferable that the ROM areas are arranged in a state grouped on asequential addresses. Concretely, for the ROM area, it is preferablethat, for example, a group of file management information data describedon the basis of the AVDP (Anchor Volume Descriptor Pointer, located in257th address of the logical addresses) is written with RAM data andthen arranged in a state where grouped.

Accordingly, when the size of the RAM data increases due to the rewriteof another RAM data or the alternate sector process, the addresses ofthe RAM data are free from separated, which is desirable on the systemin shortening the access time and simplifying the file managementinformation.

Also in all the cases shown in FIGS. 12( a) to 12(d), if a RAM areaexists although partially and the contents of the user data area arerewritten, it is preferable that the lead-in area is rewritable. Becausethe PMA area also retains file management information temporarily aswell as the lead-in, RAM data is preferable thereto.

However, in a case in which the lead-out area, particularly, the ROMdata in the first session shown in FIG. 12( a), comprises a pre-pitsrow, it is preferable that the lead-out in the first session is formedwith pre-pits. Since the lead-out data is never rewritten, the formationthereof with the pre-pits creates no problem if the address is fixed,and it is possible to omit the time needed for the formation of thelead-out by recording. In addition, in the file management informationwritten in the PMA, only the information related to the first sessioncan also be written with master ROM data comprising a pre-pits row.

Preferably, the above-mentioned recording processing of the lead-in andPMA (when needed, the recording of the lead-out) are conducted in amanufacturing process at a factory and the user side can read out theROM data immediately without conducting the pre-processing or canconduct the writing in the RAM area.

Incidentally, in the case of this CD-RW disc 10, it is necessary thatnot only the ROM area but also the RAM area are recorded with an EFMsignal and the absolute information depending on a subcode continuesseamlessly. Usually, it is necessary that the linking between the ROMarea and the RAM area corresponds to a linking between tracks orsessions each forming an unit of data in a compact disc. For the linkingof data, there is a need to apply a linking rule at the additionalportion of data prescribed in the CD-RW standard (Orange Book Part 3).In particular, preferably, at the linking between a ROM area formed withEFM signal data comprising a pre-pits row 52 and a RAM area, in order toavoid the presence of a non-recorded area between an EFM data signal tobe overwritten and an EFM data signal of the pre-pits row 52, therecording of the EFM data to be overwritten begins to make the overwriteon the pre-pits EFM data signal in a range of approximately two EFMframes. Since the data of the pre-pits row 52 cannot be erased in theoverwritten portion, the two types of data are placed in a state mixedto cause partial destruction of the EFM signal. However, in a range tothis extent, the correction is possible by an error correctioncapability of a CD readout system, and the error does not propagate intothe data outputted from the readout drive unit.

Thus, in the CD-RW disc 10, a logical ROM and a write-once type disc arerealizable, and in a P-ROM disc having ROM data partially, it ispossible to facilitate the identification of the ROM data and the RAMdata, and further to construct a practical file management method.

(B) Other Modes

The present invention is not limited to the above-described embodimentsand modifications thereof, and it is possible to cover all changesthereof which do not constitute departures from the spirit and scope ofthe invention.

Although the above description has been made considering the case of theuse of the mode 1 format, other modes are also usable, and thedifference between the modes does not affect the spirit of the presentinvention. In addition, although the multilayer structure has beendescribed as being six layers as an example, the invention is notlimited to the six layers.

Furthermore, the above description is not limited to the CD format but,for example, is also applicable to ADIP (address-in-pregroove) providedfor an object similar to that of the ATIP. This ADIP is made to simplyexpress an address in terms of a sequential integral numbers but not interms of time. Moreover, the recording drive unit can add data with thesame contents through the use of this.

In addition, as the wobble, it is also possible that both side walls ofa groove are made to meander, or that one side wall of the groove isformed to meander. In the case of the meander of both the side walls,the meandering frequencies or modulation modes thereof can also bedifferent from each other.

Still additionally, it is also acceptable that the wobble is realizedwith another periodical groove deformation, for example, with avariation of the depth of a groove. Naturally, this is also applicableto a medium which does not have a groove pitch made to be approximately1.6 μm like the CD format, but which has a higher-density track pitch.

As the basic data unit written with a recording data row based on apre-pits row or a phase change, there are a case in which auxiliary datasuch as address information is added as bit information similar to userdata as well as the aforesaid subcode Q channel of the CD-RW format orthe header information of the CD-ROM format and a case in whichauxiliary data such as address information is previously written with awobble or on a flat portion between grooves or pre-pits rows. Forexample, giving the auxiliary data by the wobble corresponds to theaforesaid ATIP frame of the CD format. On the other hand, deformedportions such as irregular pits or recording marks can be formed on aninter-groove portion between the adjacent grooves or a flat portionbetween the adjacent pre-pits rows. FIG. 20 show a case in which pitrows are provided between pre-pits rows and between grooves to giveauxiliary data including addresses. Although a portion between groovesis commonly referred to as a “land”, a flat portion between pre-pitsrows can also be considered as a land in a wide sense, and deformedportions such as pits are provided in the wide-sense land portion alonga data row of a basic unit of user data to give auxiliary data such asaddresses. Also in this case, preferably, the auxiliary data informationincluding addresses shown in FIG. 20( a), based on pits in the flatportion between the read only area pre-pits rows, and the auxiliary datainformation including addresses shown in FIG. 20( b), based on pits orrecording marks between grooves in the recordable area, have the samelogical structure, and the addresses continue in the read only area andthe recordable area. Moreover, preferably, in addition to the user data,these auxiliary data have the equivalent physical signal characteristicsin the read only area and the recordable area.

Furthermore, although the above-mentioned contents include, as anexample, the identification information representative of a disc orP-ROM or the address information of the ROM area in units of tracks orsessions, which is written in the subcode Q channel in the lead-in, itis also possible that they are written in the main channel of thelead-in area.

In this case, the address information of the ROM area signifies at leastone information (address or size) of a start address, end address andsize (data length) in each ROM area. Moreover, in a case in which eachROM area includes a plurality of user data files, when file managementinformation is added for controlling the file structure (directorystructure, start/end address of each file, or the like) thereof, it canbe considered as the address information of the ROM area in a widesense.

In this case, it is also possible that the main channel of a portion ofthe addresses in the lead-in area is allocated to the writing of theaforesaid address information of the ROM area so that the addressinformation of the ROM area is entered in the main channel of thelead-in area in the form of pre-pits. For example, since, at therecording of fixed-length packets, a large number of fixed-lengthpackets are formed also in the lead-in as shown in FIG. 10, it ispreferable that the aforesaid address information is written in the mainchannel of the user data block of a portion of the packets in the formof pre-pits.

In this connection, in a case in which the address information of theROM area is recorded as master ROM data in the lead-in area, it is alsopossible that the ROM data is made with a wobble or the like modulatedat a high frequency, instead of the pre-pits.

(C) Application Examples

A description will be given hereinbelow of application examples foreffective use of a rewritable phase change medium having a read onlyarea according to the present invention and execution means thereof.

A preferred mode of a P-ROM medium according to the invention is amedium having a read only area including a first read only area in whichdata is recorded in the form of pre-pits rows and a second read onlyarea formed by inhibiting re-write of data and further having arewritable area. In this case, the first read only area is a master ROMarea while the second read only area is a post ROM area. That is, theaforesaid medium according to the preferred mode is made such that allthe three types of areas: the master ROM area, the post ROM area and theRAM area, are placed on the same disc.

The content to be described hereinbelow is a concrete applicationexample of a medium having these three types of areas.

Two types of data: a main routine comprising an execution program and acustomized demonstration data collection comprising a plurality ofcontents, are collected as ROM data. For example, the main routine is aprogram which starts up a menu screen as a user interface and implementsvarious types of processing in accordance with the user's selection.When the user selects the implementation of a specified demonstrationthrough the use of the menu screen, the selected data is drawn from thedemonstration data collection and the demonstration is implementedthrough a program of the main routine. Following this, the user dataobtained through the repetition of the demonstration by the user or thelike is recorded in the RAM area.

Furthermore, the program of the main routine is stored in the master ROMarea, and in order to achieve the customizing for offering a differentcontent to each user, the demonstration data collection is stored in thepost ROM area, and the user data is recorded in the RAM area.

The case of a rewritable type compact disc will be considered for aconcrete description.

In such a medium, it is preferable that the application program and theuser data are recorded in fixed-length packet units having the same filemanagement structure, and that a file management method according to theUDF format is employed.

That is, for example, data is arranged on a recording medium as shown inFIG. 17.

FIG. 17 is an illustration of an example of an arrangement of P-ROMdata. The P-ROM medium shown in FIG. 17 is such that an application areastoring predetermined application program data is formed in consecutiveareas at the innermost circumference of the program area AC shown inFIG. 4( a) as the first session having a ROM attribution, and a userdata recording area, in which user data related to at least theaforesaid application program is recordable, is set in the remainingareas as the second session having another RAM attribution.

At this time, the ROM attribution session (program area 150 of the firstsession) including the application program is composed of both a masterROM area 152 and post ROM area 153. This ROM attribution session (themaster ROM area 152 and the post ROM area 153) is closed with a firstsession lead-in area 141 and a first session lead-out area 160, and theRAM attribution session (RAM session) is closed with a second sessionlead-in area 142 and a second session lead-out area 161. Moreover, boththe first session and second session have the packet structure shown inFIG. 10 according to the prescription of the UDF, and in the secondsession including a RAM area 154, the block structure shown in FIG. 10is previously recorded with RAM data and formatted according to theprescription of the UDF.

In addition, the attribution of the entire first session including theapplication program is set as a write inhibit (read only) attribution,and a master ROM area comprising a pre-pits row and a post ROM areacomprising a non-recorded area (where only a guide groove exists) arecontinuously formed in the first session program area 150. The end ofthe master ROM area 152 and the start of the post ROM area 153 areconnected to each other through the link block 25 a shown in FIG. 10.

Still additionally, preferably, a read only or rewritable attribution isgiven in session units, and a data attribution is prescribed in ATIPframe, EFM frame or block units. That is, a write inhibit (read only)attribution is given to the master ROM area 152 comprising a pre-pitsrow, while a write-once (first-time writable) attribution is given tothe rewritable non-recorded area. Most preferably, as mentioned above,not only the pre-pits row of the master ROM area 152 but also the grooveof the post ROM area 153 are wobbled to give a data attributionaccording to the ATIP.

Moreover, the recording of each of the master ROM data and the post ROMdata is made only on the factory or software manufacturer side, andafter distributed to users, is recognized as a write inhibit (read only)session on the basis of the attribution prescription on the firstsession on the user side.

Still moreover, the switching from a pre-pits row having a wobblingcenter line from a wobble is made at the boundary between the master ROMarea 152 and the post ROM area 153, and addresses based on ATIPinformation are continuously given.

In particular, if an application for language practice is taken as aconcrete application example of the latter, a basic routine (executionprogram) 155 for implementing demonstration data on the basis of themenu screen for the user interface in FIG. 17 or the selection from themenu screen is stored in the master ROM area 152. This basic routine ismade as a master ROM because of not depending on the type of foreignlanguage to be learned, that is, because of not depending on a userbeing an object. The main routine is displayed in the mother tongue of alearner, for example, in Japanese.

In this case, the demonstration data corresponds to the pronunciation ofa phrase presenting a model, and is stored as the demonstration datacollection 156 in the post ROM area 153. The contents of thedemonstration data vary between different languages, and are recorded inthe post ROM area 153 on the factory or software manufacturer side. Thecontents comprise a plurality of phrases, and the phases are separatelyset as data 1 of a demo 1, data 2 of a demo 2, . . . , data n of a demon, and are arranged so that the direct access to the data of everydemonstration number can be made in accordance with the selection fromthe menu screen. The data produced with a user repeating the phrases ofthe demonstrations are converted into a digital form through an ADconversion to produce repetition data 1 of the demo 1, repetition data 2of the demo 2, . . . , repetition data n of the demo n which in turn,are stored as a table (demonstration repetition data collection) 157 ina RAM area 154.

As an execution means using this medium, a recording/readout apparatusaccording to the present invention forms, as a session (read only area)having a ROM attribution (read only attribution), an application programarea storing predetermined application program data in consecutive areasat a inner or outer circumferential side of a program area whilesetting, as another session (rewritable area) having a RAM attribution(rewritable attribution), a user data recording area, in which user datarelated to at least the application program is recordable, in theremaining areas of the consecutive areas, and conducts the readout ofthe application and the recording/readout of the user data related tothe application. In addition, the recording/readout apparatus proposedaccording to the invention is made up of a recognition means foraccommodating the foregoing disc-like medium and for recognizing thepresence of a P-ROM (a rewritable phase change type optical disc havinga partial read only area), a program execution means capable of gainingaccess to a ROM session recognized by the recognition means to acquiredata of an application program for executing the contents of theprogram, an information inputting means capable of inputting necessaryinformation in accordance with the application program executed by theprogram execution means, and a recording means capable of gaining accessto the user data recording area to record, as user data, the informationinputted through the information inputting means.

FIG. 18 is a flow chart for explaining a recording/readout method for aP-ROM. This flow chart is realizable with, for example, arecording/readout system shown in FIG. 19. FIG. 19 is an illustration ofa configuration of a recording/readout system according to an embodimentof the present invention. This recording/readout system shown in FIG. 19includes at least a CD-RW disc (P-ROM disc) 210 having a partial readonly area, a recording/readout apparatus 220 for conducting therecording/readout on/from the medium, and a host computer (host PC) 230connected to the recording/readout apparatus 220. The host computer 230includes an interface for the input/output with respect to users. Therecording/readout apparatus 220 and the host computer 230 are connectedthrough a data transfer line 240 to each other to achieve mutual datatransfer therebetween. A CPU 250 of the host computer 230 decodesapplication programs. A temporary storage memory 260 thereof is a solidstate memory or hard disc, and is used as a work space in the middle ofthe execution of a program.

The processing starts at a step S0 in FIG. 18, and a P-ROM discaccording to the present invention is mounted at a step S1. At thistime, usually, the rotation of the disc starts, and the focusing,tracking servo and others are set up. Subsequently, at a step S2,control information on the disc are read out from a lead-in area, a PMAarea and a PCA area. This disc control information is information onoptimum recording power at recording or linear velocity, and is formaking a decision that the disc is of a CD-RW type and of a P-ROM type.

Then, at a step S3, from the lead-in area and the PMA area, a decisionis made that the disc has a multisession. Moreover, file information isacquired from a program area of the first session forming a ROM session.

The processing from the step S1 to the step S3 is implemented in theCD-RW recording/readout apparatus 220. In more detail, in each of thesteps S1, S2 and S3, a flow is implemented as shown in the flow chart ofFIG. 15.

Following this, at a step S4 of FIG. 18, data of a main routine of anapplication program in the master ROM area on the CD-RW disc 210 is readinto the host computer 230 so that the CPU 250 of the host computer 230implements the following steps while interchanging data with therecording/readout apparatus 220.

Usually, as indicated in a step S5, a menu screen serving as a userinterface is initially started up to make a user select the followingoperation of the execution program. At this time, at step S6, theimplementation of a demonstration and the contents of the demonstrationto be implemented are selected and the implementation start of thedemonstration is directed. In this case, the demonstration firstselected will be referred to as “demo 1”.

Furthermore, at a step S7, a predetermined address in the post ROM area153 of the CD-RW disc 210 retaining the concrete contents of thedemonstrations is accessed to acquire the data on the demo 1. Usually,this data is temporarily stored in a temporary storage memory, such as asolid state buffer memory or hard disc, in the host computer and thenread out from this temporary storage memory 260 to be converted into avoice or image and used as a demonstration at a step S8.

For example, assuming that the application is a language practice or thelike, in the process of executing the application program, ademonstration for uttering a predetermined sentence is read out to makea user input information according to that demonstration.

Still furthermore, at a step S9, an interruption 1 from the user takesplace, and if the data input is not made from the user, a route R1 istaken to repeatedly conduct the demonstration, and if the interruption 1to the effect of the shifting to the user data input is executed, at astep S10, the RAM area of the CD-RW disc 210 is accessed and falls intoa waiting condition, and at a step S11, the data input is made from theuser. In an example of the language practice, this corresponds to therepetition of the contents of the demo 1 by the user. The voice data isAD-converted in the host computer 230 and temporarily stored in thetemporary storage memory 260 in the interior of the host computer 230.In addition, it is also possible that the user data and the data of thedemo 1 are allocated to the left and right channels, respectively, andcombined for the stereo recording. This facilitates the comparisonbetween the contents of the demo 1 and the contents of the repetition bythe user.

Thereafter, at a step S12, the data is transferred to therecording/readout apparatus 220 and the user data is recorded in the RAMarea of the CD-RW disc 210, and at a step S13, the data inputted by theuser is immediately read out, when needed. At this time, in an userinterruption 2 at a step S14, a route R2 for re-inputting user data or aroute R3 for returning to the repeated implementation of the demo 1 isselectable, and if not required, at a step S15, a selection is madebetween the shifting to the next demonstration (demo 2) and thetermination of the demonstration. In the case of the shifting to thenext demonstration, a route R4 (YES route) is taken for returning to thestep S6 to conduct the demonstration selection operation.

For the termination thereof, a NO route is selected so that, at a stepS16, the file management information is updated on the basis of the userdata newly recorded in the RAM area and at a step S17, the demonstrationcomes to an end, and the operational flow returns through a route R5 tothe menu screen.

In addition to the above-described concrete example such as languagepractice, the CD-RW having three types of areas of a master ROM, postROM and RAM according to the present invention can also accept a usingmethod in which an application program of the first version is stored inthe master ROM area and, when a partial version-up (updating) thereof isneeded, only a portion required for the program correction is stored inthe post ROM area. It is also possible that the first-versionapplication program is made as a updating-unnecessary basic programcommon to all applications to be added as a post RAM afterwards.

Still additionally, in FIG. 17, although the master ROM, post ROM andRAM are arranged in order from the inner circumference, it is not alwaysnecessary that this order be taken. Moreover, it is also possible thatthe master ROM, post ROM and RAM are arranged according to the UDFformat which does not make the partitioning into sessions as shown inFIG. 12( c).

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, in a rewritablephase change type disc, particularly, a CD-RW, three types of dataattributions of write inhibit (read only), write-once and arbitraryrewrite can be prescribed according to frame of 1/75-second unit forminga basic unit of data in a CD format, or according to block of user data.This enables the intended rewritable type data to be handled as logicalROM data. In addition, the CD-RW can apparently be used as a write-oncetype medium.

Moreover, in a P-ROM disc in which a physical ROM area comprisingpre-pits or the aforesaid logical ROM area and a RAM area are mixed andboth coated with a phase change medium, it is possible to inhibit theoverwrite on ROM data, thus preventing the destruction and falsificationof the ROM data.

1. A read only data erasing method for use in an optical recordingmedium in which a phase change type recording layer is formed onsubstrate and read only data is made by a plurality of pre-pits rowsformed on said substrate, comprising: overwriting said read only data insaid phase change type recording layer with data having a contentdifferent from a content of said read only data so that said read onlydata is erased, and returning said read only data erased by saidoverwritting to a non-recorded state, wherein said read only data in thenon-recorded state is readable again.